Personally I prefer to hire on eLance more than anywhere else.
When I have a graphic design project, I'll almost always post it on freelancer though, because I always get two to three times as many bids on my graphic design projects on freelancer than I do on eLance.
When I have a "programming" job of almost any kind, I always put it on elance because I get far better & more qualified candidates on elance for those types of jobs.
As I said, I prefer elance overall, but freelancer does have it's purposes for me anyway.
Sorry OP, I know you were looking for an answer to this question more from a freelancers point of view than a clients point of view, but I figured I'd throw my hat in the ring and give you my opinion from my perspective anyway...maybe it'll help.
(P.S. - I hate oDesk)
