I got Dragon Age on the PS3 and really enjoyed it. But I do think that if you don't mind playing on a PC then Bioware games do tend to be best there.
If there ever is a PS3 version of Mass Effect 1&2 I think we would first hear about it in about 6 Months. Judging by the standard lenght of exclusivity agreements my guess would be that Microsofts old agreement with Bioware would be due in about such a time. Unless of course Bioware signed away for all 3 games from the beginning, and thus exclusivity would only end about 6 Months after the release of the third game. But that would be a rather unique agreement if it was the case.