I have been very happy with my 5'8" custom fish. I can take it out as long as there is enough wind to keep my 11 in the air, and I have had it out in 35-40mph on my 7m. Really fun board, quality is pretty nice too. Still riding it strapped. If you want to go strapless your prob better off just getting a beater used shortboard... alot cheaper.
Here is a link to my overview of the board.http://masskiting.com/kiteboarding-forum/new-toy-2011-naish-58-custom-fish