I bit the bullet and bought an Exped dlx9. Not cheap at 175 euros, but i know from experience that youll pay anything in the middle of the nite when your cold and tired!!
I tried in the shop laying on the exped and the thermarest. To be honest the thermarest felt better to lie on, but its a perfectly flat shop floor. What did it for me tho was the size of the exped over the thermarest, i travel mostly with my woman so everything is doubled!
Just back from Poland, slept like a log, better than my own bed. I dont have an expensive sleeping bag and the only time i woke up in the nite was from a cold ass. It was just off the exped, not even on the ground. Rolled over a bit and i was instantly warm and sleeping like a log.
Cant recommend exped highly enough!