I've played Project x, 6.0 shafts for the past 5 or so years. This year purchased a new set of Titleist 712, AP2's with KBS, C-Taper, Stiff shafts and I love them.
I hit my irons high and with a touch of a draw. I decided on the CT's in an effort to bring my ball flight down a touch. If I'm swinging well and consistently, they have done just that. Slightly lower ball flight, less spin, little more yardage and still holding the greens fine (I play a pretty fast home course - The Patriot Golf Club). Playing a ProV1x.
The PX shafts were stiff and relatively abrasive at impact. The CT's feel stiffer, but are smooth as butter if I hit it on the screws.
DB