TORONTO - When looking back at 15-plus years of making records, Canadian rapper Buck 65 doesn't have a hard time picking favourites.

But recalling his personal highlights, Buck 65 doesn't immediately think of the early avant-hip-hop records that won him widespread critical acclaim. Nor does he point to 2004's "Talkin' Honky Blues," which won him a Juno Award.

Instead, the rapper (whose real name is Rich Terfry) looks to his three-part "Dirtbike" mixtape series, modestly put together at home and released for free.

Though the 2008 recordings lacked the five-figure budget of a proper label release and included mistakes (Terfry admits he accidentally taped some vocals with the microphone facing the wrong way), those mixtapes stand among the performer's personal career highlights.

"In a lot of ways, there's just no comparison between my performances -- and in a lot of ways the material -- on 'Dirtbike' compared to some of my other releases," the Mt. Uniacke, N.S., native said in a telephone interview on Monday.

"(It's) maybe a weird thing to admit, (but) of all the stuff I've done, it's what I listen to the most."

It actually isn't that weird at all.

In hip hop, it sometimes seems rappers release mixtapes with the casual ease of a baseball flamethrower tossing out warmup pitches.

Mixtapes -- typically assembled hastily and released for free -- have become pretty much a necessity for rappers looking to create buzz, whether they're being passed out on a street corner by fledgling MCs or being dropped digitally by multi-platinum superstars.

Over the past year, artists including Toronto rapper-crooner Drake, the Technicolor talent Nicki Minaj and the charming Atlanta MC B.o.B have successfully translated mixtape buzz into chart success and Grammy nominations.

But plenty of others have faltered, failing to live up to the hype generated by their mixtapes.

Looking forward to 2011, it's tempting to forecast a big year for several beloved mixtape fixtures surfing a wave of advance attention, including J. Cole, Wiz Khalifa and Jay Electronica.

But if the past years of buzzy busts have taught us anything, it's that Public Enemy's old edict still rings true: don't believe the hype. Some in the industry are finding that many rappers' albums simply aren't living up to their mixtapes.

"In a lot of scenarios, it is (true)," Toronto rapper Kardinal Offishall said.

"It's because there's no pressure when making a mixtape. It doesn't matter how many units are downloaded ... it's just a lot more freedom to just be you and do what you wanna do."

Of course, mixtapes have existed as long as hip hop itself, whether as the sole method of capturing the blistering live shows of the '70s or as compilations curated by DJs in the '80s.

Over the past decade, mixtapes have gathered steam as the rap genre's promotional tool of choice. Given how convenient it now is to offer up a new collection of tunes for free Internet download, mixtapes have become an essential tool for rappers to either earn new fans or keep old ones engaged.

Perhaps the poster-child for the power of the mixtape is Lil Wayne. The New Orleans rapper built a deafening buzz with a cluster of classic releases -- his "Dedication" and "Da Drought" series -- in-between the scheduling of his "official" albums, the "Carter" series.

"Tha Carter III" dropped in 2008 and went multi-platinum in Canada and the U.S en route to four Grammy wins.

Drake later followed a similar model, with his "So Far Gone" mixtape building an audience prior to his official debut, the platinum-selling "Thank Me Later."

Still, many other rappers have struggled to live up to the expectations created by those quickie releases.

Washington rapper Wale built a profile through a series of promising mixtapes, culminating in the "Mixtape About Nothing" -- an 18-song tribute to "Seinfeld" that caught the attention of fans who appreciated his irregular flow and easy juxtaposition of clever, goofy punchlines and serious subject matter.

But when he released his long-awaited debut full length -- replete with major-label backing, a slick advance single featuring Lady Gaga and production from Mark Ronson and the Neptunes -- fans were disappointed.

The record opened at No. 21 on the charts but fizzled afterward, while the critical response was lukewarm, at best.

The New York Times wrote that Wale's mixtapes, "with their low-budget production but far-reaching rhymes, now testify to how much Wale decided to conform" on his debut, while Pitchfork wondered whether Wale had "said too much already" prior to even releasing his first album.

A similar fate found Cleveland rapper Kid Cudi, whose debut "Man on the Moon" was panned by the Times as being "several notches below last year's often spectacular mixtape 'A Kid Named Cudi."'

And even the artists who have actually retained their audiences with the jump to more polished records have faced criticism for sacrificing their rougher edges.

"How much in the last couple weeks, for example, have I been reading all this response to the Nicki Minaj record, like, 'Oh man, where's all the excitement from the mixtapes gone compared to this record?"' Terfry said.

"If I was advising young people, I would kind of just caution them a bit: Be really careful about the way that you build expectations around what you're doing, because it'll be hard to live up to."

"It seems that the potential for disappointment is so high. You're setting yourself up for failure when you start in a completely unfettered way like that. I mean, I can't really think of an example of any of those 'mixtape phenomenon' rappers who put out ... a long-awaited debut where it was better than the mixtapes.

"I can't think of one."

Even in Lil Wayne's case, "Tha Carter III" was a megahit and still left plenty of fans disappointed.

On his mixtapes, Wayne tore beats apart like a gleeful little gremlin, happily indulging in esoteric pop-culture references with free-associative verses that recklessly careened around the depths of his creative mind.

"Tha Carter III" had some of that too, but it also downplayed his idiosyncratic side in favour of innumerable guest appearances and club-friendly production.

"(He) just built it and built it and built it for years into this incredible volume of work and mixtapes," Terfry said. "But I don't know anyone, of all the Lil Wayne fans I know, that loves that album better than any given mixtape he made before it."

Indeed, there are several reasons why these official album releases have been letting down fans.

For one thing, mixtapes tend to be "free" in more than one sense of the word. Oftentimes, artists are liberated by the lack of expectations, budgets and label interference. They can be themselves, without worrying about the chart.

"Somewhere in the back of your mind ... you're saying to yourself: 'I'm not really going to second guess a lot of my creative ideas in the way I would if I was trying to make money off this thing,"' Terfry said.

Still, there's the small matter of earning a living, and there's no money in mixtapes.

"This is the music business, so you can't just make the music and not care what happens to it at the end of the day," Kardinal Offishall said. "No matter what cool artist wants to be like: 'Man, I'm just doing this for the love and express my creativity, blah blah blah.' If you don't make a good song, you might as well just give away your music for free on the street corner.

"The reality is, when you're involved with major labels, or even if you're doing it independently, and you're trying to get consumers to purchase and buy into what you're doing, there's certain things unfortunately that you have to do."

Yet the lack of money to be made in mixtapes is part of why they're often so good: there's no need to clear samples on a record being distributed for free.

Toronto electro-pop outfit Woodhands released their first mixtape, "No Feelings," in September, splicing up tracks from their own albums and using them as bed tracks for a cappella verses from rappers including Lil Wayne, Ludacris and Eminem.

Their motivation was simple -- they simply love mixtapes. And frontman Dan Werb theorizes that those records are as good as they are because artists can use restricted samples without fear of litigation -- citing, for example, B.o.B's "Lonely People," which samples the Beatles' "Eleanor Rigby."

"That song is amazing, but there's no way that they'd be able to ever clear that sample," he said.

"I can't just take a Ludacris a cappella and throw it on an album. But if you give it away for free, you can totally do that."

Some, however, argue that the term "mixtape" is fast becoming out of date.

Brooklyn rap trio Das Racist has drawn a groundswell of buzz for a pair of mixtapes released in 2010: "Shut Up, Dude" and "Sit Down, Man." The records (both available for free online) have earned spots on year-end best-of lists by Pitchfork, New York magazine and Rolling Stone.

But their beats are mostly original, not cribbed from other popular tunes. Their hyper-literate lyrics, a stunning mix of junk-culture references, pop parody and semi-serious racial provocations, are more carefully considered than almost anything on the charts.

"The lines are blurring," said the group's Ashok Kondabolu in an email.

"I think a lot of it is semantic these days. Our mixtapes are almost completely original music, but we decided to call them mixtapes."

Added groupmate Victor Vazquez: "The mixtape as an idea is more suited to our times than the album as an idea."

But other artists still see a clear distinction between mixtapes and proper albums.

Edmonton rapper Roland Pemberton -- a.k.a. Cadence Weapon -- recently dropped "Tron Legacy: The Mixtape" (the title is a winking reference to other movie-themed rap mixtapes, not an actual tribute to the Disney film).

He's planning on releasing a proper new album, "Roquentin," in 2011. But he said he had some ideas he wanted to explore that wouldn't fit in with that record.

"The stuff that's on my album is way more high-concept and way more thoughtful," he said.

"This mixtape is totally like a catharsis. I had these interesting ideas but not really important, life-changing concepts.

"Like I don't want my album to have a song about weed on it."

It's fair to say that "Roquentin," meanwhile, will be a more ambitious affair. He's devoted years to crafting that record, which will feature live instrumentation and inspirations well beyond the realm of hip hop, including Grace Jones and the Talking Heads.

Still, he jokes that fans might well prefer the mixtape over the proper record.

"I worked for three years on this album," he said, before laughing.

"(People) are going to be like: 'Yeah, the mixtape was way better, man."'

-- With files from Canadian Press reporter Michael Oliveira in Toronto