If you think about transfers to OU over the years, I think most have worked out fairly well. Jabari Brown was a transfer and worked out really well. Osby seems to be working out well. Ryan Wright was a repsectable contributor. M'Baye is reportedly going to work out well.
Ray Carruth is about the only transfer I can think of that did not work out well. There are probably some others I am not recalling.
Note I am not including juco transfers in this group but for the most part those guys have worked out pretty well too.