Wintec and Bates aren't that different, considering Bates owns Wintec! Wintec is really just the synthetic range of Bates saddles.
I own a wontec 500 AP, I have owned it for eight years now and it is the comfiest of all my saddles. They are very hardy, mine has been knocked around a lot, and has been used on about 5 different horses. Once you build up a collection of all the different gullets it really is so easy. The only problem I have found with wintecs is the gorth points, the plastic covering the nylon around the holes tends to break and warp after time, making it hard to do up the girth. I got mine replaced with leather points, and have never had a problem since.
I also just bought a Bates Kimberly Swinging Fender, which is a stock saddle, but it is beautiful. My horses all go much better under it than any of my other saddles.
I think in deciding between the leather Bates and the Synthetic Wintec (seeing as they are practially the same saddles only in different material) is wether you want the convenience, lightness and weatherproofness of the synthetic or the look, feel and durability of leather.
Good luck in saddle hunting!
Theres nothing like that first ride in a nice new saddle...