I have also heard some saying that SC antibodies are not good. The reason being so many people are still likely to use their antibodies is because many of their antibodies are published on paper.
I personally have been using some SC antibodies. There are indeed some antibodies that produce false positive staining, but they do have good ones too. If you do IHC, try DAKO, Chemicon, Novocastra, Lab Vision, which are good IHC companies.