Just purchased Exped UL Downmats for me and the wife - extremely pleased with purchase - so much more comfortable than our thermarests were and about the same weight.
Thermarest is somewhat lighter on web-specs for comparable size but also likely noisier due to construction and fabrics used (crinkly) as with other neoair. Downmat is silent. Just weighed my Medium size downmat and it comes in at: 678g including stuffsack, inflation sack and included repair kit...but extremely comfortable 4 season mat - can thoroughly recommend.
Edited: 16/06/2012 at 11:59