which tuner is better?

They are both practically the same tuner, one tuner just has more features than the other.

From sources and other members, yes majority are using SCT. Others prefer Diablo, but Diablo does has it's problems. Friends of mine, had Diablo and switched to SCT just recently. Diablo has constant updates and software upgrading and people often lose tunes on their diablo for some strange reason, and lots of times when people load their tune, they get error codes, CEL or sometimes the tune doesnt load. Happened to two of my friends who had the diablo. Further more, it seems a lot of Diablo tuners dont have great customer service.

So I took the plung on an SCT and I love it! I've had no problems, no error codes, nothing! And it is by far the best tuner out on the market! My friends who have switched from Diablo to SCT highly agree and wish they had bought the SCT first.

If you plan on going with an SCT Tuner, I highly recommend going to this guy. He has known to be a great tuner on a lot of these forums and I'm not sure if he is a member on this forum.

Doug @ BamaChips
www.bamachips.com

He offers GREAT, and I mean GREAT customer service, Bang for the Buck tunes and has an outstanding reputation amongst other members and customers from all over and on the forums. He is great, you tell him what you have got on your car, and what you want, and he will give you what you want! More Power!