So, I recently created an oDesk Buyer's account -- I wanted someone to redesign the front-end of a website. I don't have the time, skills, or aesthetics sense to do it myself as quickly as I want, and so like all great Americans, I'm willing to throw money at the problem until it goes away. =D
I chose oDesk because I'm comfortable with how it works from the provider's point of view. There's a few downsides to having both types of accounts (they're not tied together Single Sign On style): you can't use the same email address you use as a provider, although if you're using gmail you can use an address like email@example.com and it'll work.
Signing up was pretty easy -- took me about a minute, 30 seconds of which was trying to figure out whether it was a + or a - in the trick I just described above.
Lots of candidates, but I've noticed some providers just spray and pray -- not reading the cover letter is a good example of this, but inviting a provider to an interview and then having them cancel a day later due to them trying to "maintain their job application quota" is kinda like, "omg wtf?"
I've narrowed it down to about 3 providers -- I know for sure I'll pick one of them, so I wish I could close or hide the job entry so new applicants can't waste their time applying to it.
Also, interestingly, one of the provider's emails went straight to gmail's spam box. The weird thing is, nothing in the email seems like it would have marked it as spam.
Anyway, so far so good. It's kind of a pain working at oDesk + buying from oDesk, since I keep having to sign out of one account and into another, but, besides that, big thumbs up, yo.