I use the Thermarest "Original" and find it much better than a normal foam
mat. Yes, they do self inflate, but I usually give them a few puffs until I
hear escaping from the valve, as opposed to going in.
Deflation is easy too, though it takes a little practice and patience to
get it back into its stowage sleeve. Open the valve and start to roll the
mattress very tightly and slowly, from the far end. An extra minute spent
doing this will ensure that all the air is expelled first time, otherwise,
you have to unroll and start again.
Condensation does seem to be a problem in "Modern" tents. I use a Terra
Nova Super Nova for static camping and a Terra Nova Voyager for backpacking.
I overcome most of the condensation problems in the Super Nova, by leaving
front and rear doors open at the top an inch or so. This allows a good
through-flow of air. However, cannot do that in the Voyager, as it only has
the one door.
Having said that, I would prefer to put up with the problem of a little
condensation, but having the knowledge that the tent will still be standing,
despite whatever weather the UK mountains can throw at me.
Paul