I'm a beginner with such performant race boards, so I can't compare. but I can say I'm happy with my Royal K. stealth 70!
there was a few problems with mine but nothing really bad (I had to add some resin in fin boxes, to glue the pads, and to change the back strap).
it's a really fast board, and it seems very strong. I will use faster fins to increase the VMG.
by the way a nice vid from Gunnar Biniasch, (flysurfer team) http://vimeo.com/32115045