I managed to get a wide roll a cot last minute right before my Grand Canyon trip and I was super glad to have it. I slept on my "Guide" Paco Pad one night just to see the difference, and instantly went back to the Cot. I actually used it on my boat most nights and it worked great. Used it on shore a few nights when it was a crazy eddy and it was great there too. I'm a total convert now.
I never needed a pad or anything since it was pretty warm. Just by itself its plenty comfortable, but its kinda nice to have something between you and the cot like a sheet since its got a plastic/vinyl feel to it.
We had mosquitos a few nights and I actually set my tent up and layed it over the cot just to keep the bugs off on one of them. It looked a bit silly but worked well.
I used my fleece bivy on quite a few nights and it actually worked well to just use it like a blanket with nothing on the cot. It actually worked perfect with cool air under and warmth over you.
Needless to say, I'm a complete convert now. For colder weather I'm sure a nice sleeping pad will do the trick to keep me warm and I bet its super comfy that way too.
Oh, and I'm a side sleeper too and a big dude, and I had no problems feeling cramped with the wide roll a cot.