(Keeping this in The Lounge for now.....)
I say SCT, but the answer is very subjective. If you have a good tuner near you, I would use whatever he uses. Is really more what is on the program and the support you get, than the actual hardware.
I have a disslike for Diablo products (which I keep to myself as much as possible). But, if I had a good tuner down the street who used Diablo, then that is exactly what I would use. That says a lot!
Also, besides chips, there are hand-held programers. If you are a Noobe to the world of chips/programers, be sure to read this thread:
http://www.mustangtuningforums.com/showthread.php?t=19