Well I'm currently flying 13m Shiva, 9m proton, and riding an anarchist board. I have no brand loyalty to flexi, bought the Shiva cos it was a cheap new kite in the style I wanted. And apart from being a little on the slow side it's been ideal for me. Easy to fly, easy to relaunch, well built. Bought the Proton cos I liked the Shiva, and again easy to fly and relaunch.
The anarchist is a nice board too compared to my learner board which is now my light wind board. Nice flex, so quite forgiving and I've had no problems with de lamination like the Hadlow boards have.
So overall I'm very impressed with their products, but think they could do more to push the brand and maybe have a couple kites for each discipline instead of just the one.