Personally, as long as they remain two separate business entities, I'm not concerned. The whole "client quality" kerfuffle everyone wants to keep starting is meaningless: there is nothing inherent to eLance OR oDesk that keeps crappy clients out. For all the flamey trollbaiting, I just checked my eLance account (I have an account on all the major freelancing sites), and I see your typical lunatics pitching insane projects for a pittance, same as oDesk:
This post is for software engineer that already completed successfully an exchange for bitcoin and other cryptocurrencies.Anyone thinking that one freelancing platform is an asylum and the other isn't is drinking some serious kool-aid. The entire "client quality" issues stem from the self-serve nature of freelancing platforms in general: without another human to say, "Hey, this is crazy and way out of your budget" what you sometimes get are clients who are projecting their hopes and dreams instead of realistic job proposals. That will never change.
All things being equal, ultimately platform preference comes down to usability and features.
Personally, I use oDesk for the simple fee structure: you get paid, oDesk gets paid. No worry about membership levels and the restrictions based on membership level. That makes oDesk's focus laser-tight on connecting freelancers and clients, and for me that's a perfect combination.