The purpose I had for my eyetv hybrid was to play gamecube on my powerbook. I can fairly confidently tell everyone that it works great with s-video. RCA video will be less quality so definitely stick to s-video. There is little to no lag, I dont notice it even in reflex games like soul calibur 2 or sports games. The quality is good, and there is tweaking available in the preferences for those of us who like optimizing everything. It will look as good on your mac as on any lcd tv I think (I may be wrong, I haven't tested this theory). The HDTV capabilities are friggin amazing. I have never had access to HDTV before and this is awesome because I live in the middle of Boston with 20 over the air hdtv channels available. BTW, I am using my fm radio's antenna to pull in all these channels (wow!!). I am doing all this on a Powerbook G4 1.5 ghz, 512 Ram, 128 mb ATI 9700 I am really happy with my purchase!