I completely disagree with anabel actually.
I've got a multitude of Bates and Wintecs and love them all. I've found that my horses move significantly better in them, they don't mold to one horse the way a traditional foam or wool flocked saddle can, and they are easily adjustable to fit most horses. Yes - there are exceptions, but I've had great success. I do prefer the Bates to the Wintec of course, because they are leather, but I've also found they tend to fit a little better b/c the leather is a little more pliable.
Anyway - they fit well in my experience, do best with a thin saddle pad, and are great and easy to maintain. Like I said I do prefer the leather, but use my wintec for trails and in inclement weather (and right now since I hav to ride with my huge knee brace...blech).
Sit in one and try it out locally if you can before you buy on ebay
to be sure it's right for you. Good luck - and I love it! :)