I want to give benefit of doubt for Robinho. He obviously joined in wrong environment at a wrong time, but he has shown flashes of brilliance, such as a game against Betis, which gives you that array of hope he will come around. In this regard I find a lot of similarities with young Titi Henry (Lazio game where he had a blinder), and I do think with right attitudes and good coaching, he could become what Henry is to Arsenal. And it gives a chance to redeem overselves.
Personally I don't think it is an end of world if neither joins us since we are well placed even for Serie A with our current attacking strenghts. But if the choice bog down to Robinho and Tevez, to me it is no-brainer Robinho.