When I needed a new set for my 15B a few years back I just got Gadringers from Eastern Sailplane. The rotary release is a hell of a lot more convenient to use than the old "puzzle" style and the free end of the lap belts pull up towards the center of the cockpit to tighten instead of the way the old style required me to pull down towards the sides - much much easier to tighten the lap belts up now. They fit perfectly into the ship too. Not even very expensive, relatively speaking. A lot less than what I spent on upgrading the vario this year!

My club has a ship with Davis belts and another with Schroth. Nothing wrong with either really but I find the Gadringers to be a little bit more comfortable. Slightly less bulky and easier to adjust.

I can tell you that the Schroth belts seem pretty rugged. The set we have are in an L-23 where they live a pretty hard life.