Jack,
I actually thought the Prior WCRs were the best boards in the tent. I rode the 163, 171, and 181 and loved them. Edge hold was incredible and the boards were all extremely stable in the turns, even when going through the afternoon chop.
What I found with the Donek FC171 (or maybe it was a 173?) was that [flame suit on] it rode just like my Factory Prime did when it was brand new. It wasn't as damped as the same-size Prior and turn-in wasn't as quick.
What I found with the Madd 170 was [super-ultra flame suit on] that it rode just like the FC171, but with better turn-in and slightly less chatter. The Prior, imo, still trounced it it every regard.
I think what people love so much about the Madd 158 is that it rides like the short board that it is. In the past two years, the "cool thing" to do on this message board was to go with a longer and longer board to get more edge hold at higher speeds. In the process, I think people forgot how much fun it is to ride a short turny board like the Madd 158. IMO, that board felt just like my 153cm Speedster SL but with less pop (which, again imo, is part of the fun of the shorter boards).
Am I the only one who thought these things?
With regard to the CF x-wing improving torsional rigidity, might I suggest that they try using either a satin weave or UD instead of a plain weave? UD would allow them to improve torsional rigidity with zero effect on the longitudinal flex. Another suggestion would be to either rotate the fabric or use [for instance] a 60º/0º weave so that the fibers run from the toe of one boot to the heel of the other. That would, in theory, move the weft closer to being in pure compression. Among other things, what would allow the matrix to act as a damper in a single plane rather than two. I know, I know - I should shut up now. :)