I use the NP floatation vest, at first it was mainly due to wearing one during my lessons, and being a newbie it gave my wife peace of mind if I wore one at first going out by myself.
So one day I left the vest at home, then the first time I crashed my kite that session I was quite surprised to be dragged underwater.
After 30 seconds I realized that I wasn't going to bob back up and I couldn't get to the surface, I just seemed to be getting dragged along at the same depth under water.
So I punched out on the safety and self rescued.
I now wear the vest every session, it gives me the right amount of flotation and one less thing to concentrate on as I relaunch.
The vest fits well, is easy to swim with, hooks under the harness hook, it can tend to ride up a bit, but that depends if my harness rides up, it's easy to pull back down, so it's not a problem.
I don't mind looking like a rookie wearing the vest, but I'm wondering at what point someone can stop having to wear a flotation vest, I don't see many people wearing them, so am curious as to how you all manage to get away without.