Hi Hobbitle,
I'm very happy indeed with my Xtherm - used for maybe 30 nights so far.
I'm happy with my technique, though there's probably still room for improvement.
1. I undo the valve while still lying on it. This makes it easy to get rid of most of the air, and stops me procrastinating over getting up.
2. Fold into thirds (crosswise), kneel on this till most of the remaining air it out.
3. Fold into thirds long ways and roll up, pushing the tiny bit of remaining air out before closing the valve.
This is a bit awkward in a one person tent, but I manage ok.
Re inflating without mouth air:
Some adapt a garbage bag, but I find the easiest way (thanks to a forum member for the idea) is to use my pack liner dry bag.
I use the little rubber tube that comes with the Xtherm. Gather the fabric about 20cms below the roll top, after 'floofing' the sac to fill with air. Gather it around the rubber tube, which you've attached to the open valve. Then lean on it, carefully keeping the seal. It took me a bit of practice, but now I usually have my mat inflated with 2 or 3 sacfuls of air.
I love my Xtherm.
Wish it wasn't as noisy when I'm sharing a tent, though, as I toss and turn a lot.