Dropped some cash for this at the last minute while buying my sleeping bag and definitely worth it. Tentmate came with a foam pad and didn't sleep well at all. With this, I slept warm and comfortably. Insulated well against the ~30 degree rainy weather and offers a good night's sleep.
Note the exterior material does tend to absorb any moisture but putting it on its edge to dry tends to fix it right up. Fairly light weight and packs to a 'decent' size. Recommend getting the stuff sack too or pull ties to keep it bundled tight while on the go though.
It does self-inflate... mostly. Leave it for about 15 minutes, give it 3 puffs of air for fairly firm, and you're good. Remember to give a pre-inflate/deflate cycle before you take it to the field. Do not expect this thing to inflate like an air mattress you pull out for extra house guests that uses a fan or something. Give diffusion a chance.