I think spec makes a good clutch. It grabs great, but it is still easily streetable with pratically the same pedal effort as stock. No matter what clutch you talk about people are going to have both good and bad experiences with it. There are so many variables that go into having a clutch that works and last that it is no always the clutch at fault. A good flywheel, proper install, and good driver (i.e. does not ride the clutch) will make a big difference. What sold me on the SPEC was that the stage 2 is a very heavy duty clutch, has practically the same pedal effort as stock (unlike the King cobra clutch from what I have heard), and a great majority of the guys with stangs run them.
They are just fine for everday driving and realtively stock cars. However, once you start to race a lot or make some real power the stock clutches just cannot hold up. I toasted my stock one at the track one day. It just could not handle the 5000 rpm lauches on drag radials.