I had a fitted one on my 1500 and it was very comfortable. The biggest problem was not being able to remove it in the rain. Even with a rain cover the sides would get wet and stay that way. Mustang used to make a lambs wool cover with vinyl/leather sides that I thought was a good idea. Hartco even made it to fit my Saddleman seat(before they were one and the same).
I have one. It was very comfy on my OE seat. I amnot sure if it will fit my aftermarket seat (Ultimate Big Boy) but will try it one of these days. It holds a lot of dust, but is cool to sit upon - no wet ars. Very nice fit to the OE seat and Utopia rest.
I purchased mine from Diamond seats and the fit is GREAT! When they get wet just wipe with a towel and most of the water will dry off. If it is a frog choker then you will need to remove it and hang it up to dry.
I love mine and my SO bought it for us. The 06' stock seat is better than previous years.