I have a Wintec 500 GP and a Wintec Dressage saddle (although I haven't ridden in the dressage one yet), the GP one is sooo comfy! I looks and feels like a leather one, but doesn't need as much looking after as one, I wouldn't swap it for a leather one!!
I've ridden in a Thorowgood, and personally I couldn't stand it! I felt like I was perched on the horses back, it just wasn't comfy at all!