I have a Kimberly Synthetic Endurance Saddle (about halfway down on this page: Synthetic Horse Saddles | Western and Australian Styles
) and I love it. It's so super comfy for me. I've spent hours in that saddle, the most probably being 4 at a time, and I've never been sore from it.
Next September I will have had it for 2 years and it still looks nearly brand new (plus some dust and horse hair, you know).
The other thing I love about it is that I can really get out of my horse's way but I never feel like I'm sacrificing security. Gah, I could go on for dayssss.