I've had three mats to date. In my opinion the best by far, is my Thermarest Neo Air. It rolls up so small, weighs so little and yet is so comfortable. I've never noticed cold coming up from the ground, through the mat and then to make me cold. I bought the 6' version and glad I did, luxury in a one man tent! Its not self inflating, takes about 40 puffs, so to make it so much easier I bought a plain bag from Thermarest which is designed for the job. The bag has a hole in the bottom which fits over the valve. All I do is roll the bag top and it forces air into the mat, so very easy (I do it 4 times) and the best thing of all is that it works and its really low tech! When not used for this purpose it doubles up as a waterproof liner to store my stuff. Brilliant!
Its only disadvantage is that it can be noisy when I turn over. I think that's because I use a sleeping quilt (no back to lie on) so I would guess that sleeping bag users would not experience this issue. I solved mine by using a fitted sheet, also purchased from Thermarest.