I ran into oDesk recently, and had a play with it:  Long story short - it has a clean UI but the fees are a joke, I pity the souls who may be forced to use it.  Clients on oDesk have tight budgets - that's ok - but oDesk skims it at every turn: between 10% commissions, withdrawal fees (even on Paypal), 6 day "settle periods" and currency arbitrage you'll need to spike your bid by 20% to come clean and order your food by cheque to balance payments. Not a recommended marketplace for professionals.