I'm short, 5'6" @ 155lbs, so my seat choices are very limited.
I have an Ultimate Lowrider on my VTX and am very happy with it. Tried two different Mustangs, and kept going back to the Ultimate.
On my Wing, I would start getting sore after a couple hours. Really wanted to go the custom route, (Rick Meyers, or Russle) sp?, but was conserned about being able to touch the ground. So I ordered an Ultimate Lowrider, fully expecting to send it back under their trial period. Put it on,,,,, not impressed. Short ride,,,, not impressed. Took it on a day trip,,,, yeah, it's a keeper. Did 4 thousand miles in 7 days, and I'm still satisfied with it.
Ultimate warns that their seats are not waterproof. Mustang says to keep their seats treated with Protect-All to seal the stitching and seams, so I do the same with both my Ultimates. Does it work? Not sure, Ultimate makes no mention of doing it. Does my butt ever get wet due to a soaked seat? No, it doesn't. Do my riding buddies' on untreated seats? Yes, they do.