Best Sleeping Pad for Side Sleepers and Comfort on the Trail?

Also a slide sleeper. I also do quite a bit of winter time wilderness traveling and my wife and I often sleep on the snow. Over the years, we’ve found a system that works well for us. We us the therma rest neo air on top of a cheap foam pad. The foam pad provides a bunch more insulation for its weight and a firm base for the neo air. It also provides a little more protection for the Neo air from ground hazards.

I have had occasion to perform a field repair on a Neo air and it is a simple process. They seem delicate, but my first neoair lasted about 500 backcountry nights.

I’m not a huge fan of the new butterfly valve on the Neo air. I find it puts a lot of stress on the pad around the valve and fear it will wear out around the valve.

The foam pad not only provides more cushion, protection and insulation, you can use it to sit on or kneel on out by the fire.

For canoe tripping I use a Therm-a-rest Mondo King 3D. I absolutely love that pad and can't wait to climb into the tent most nights. If I am trying to save weight I have an older Therm-a-rest Neoair Trekker that is pretty good. I do certainly prefer the self inflating foam pads over the air mattresses but I get a pretty good sleep from the Trekker too.

I have a Neo Air.
I'm not a side sleeper per se, I always start on my side and always wake up on my back. BTW, all my life I sleep at most 2 hours at a time, so there's plenty of side/back sleeping cycles. The Neo Air is plenty comfortable all night, but I can't inflate it fully or it will be too stiff.
I only inflate it enough so that when I put my weight on it with a single hand, I can just bottom it out. Any more air and it will be too stiff. Once my full body is on it, it's cushy and comfy...whether on my side or back.

I recently bought an Exped pad from REI. It is around 4 inches thick and designed for side sleeps. It has the highest R value I have seen up close to 8. I will be testing it out next week in temperatures around 30-35 degrees in the back of my truck.