I have heard nothing but good things about Spec. ****, there is even a shop that builds nothing but high-end race engines (Porches, Nissan, Renault, and a few Ferrari's), and they use NOTHING but Spec.
I've heard good things about ACT. Are you going to do it yourself? I replaced my clutch in February. I had never done a clutch job before so it was quite a task but I was glad I did it myself. Total cost with resurfacing the flywheel was about $200 but that was with an OEM clutch kit. It has been working great since!
I finally put my ACT clutch in myself, and realized why all my OEM clutches died. If you had to replace that clutch 3 times under warranty, you'd do a shitty job too. Its a big job and doing it twice without getting paid would suck.
It's not necessarily a difficult job, but it can be time consuming. Especially if you haven't had your exhaust off before! I enjoyed having done it myself however, knowing that everything was put together properly and that I can do it again next time it wears out.
That and I'm ghetto poor so the money savings always helps!