I've owned the WindTech Silver Bullet 57 for a few months now and couldn't be happier. I haven't ridden my other slalom or free ride boards since getting it. It planes in around 14 knots without my ineffectual pumping. There was a period of getting used to it but the WindTech team were very enthusiastic helping with set up and technique. I'm using a 6.2 and 7.0 cammed free race sails and, once planning, it just seems to generate its own speed. I was having trouble gybing smoothly but advice from the WindTech team about slightly different foot placement now has it gybing like it is on rails while maintaining speed through the corner. GPS sailing-wise I have improved on my personal bests in 2 sec, 5x10 and alpha. Actually, over the last few weeks I've improved top speed regularly after being stuck on the same PB for about 2 years. 37 knots felt controlled and comfortable so I'm sure, in the right hands (ie not mine!), this board will do over 40. The tail rocker trim adjustment made a noticeable difference in heavy river chop.
windtechwindsurfing.com/collections/silver-bullet/products/silver-bullet-57