I'm also a side sleeper. I've tried both the NeoAir and the Big Agnes Insulated Air Core, and I've settled on the BA pad (a rectangular 66" pad.) Both were equally comfortable, but the NeoAir felt fragile - it never failed me, but it never inspired confidence, either. They both seem equally warm, too, and equally easy to use; neither is as simple to use as the Thermarest you now have, since neither is self-inflating. The BA pad is definitely cheaper, and a good value for the money.

For what it's worth, my hiking buddy has my NeoAir, and absolutely loves it.

How's that for helping you make up your mind? confused