Have a chance to nab one of these cheap: anyone have any experience with then? I've been through quite a bit of the forum posts and see tons of people have and love Synmat U7's, don't think I've ever seen anyone talk about the U5's. Other than the cold rating, is there any other differences anyone is aware of that'd make the U5 a poorer choice than the U7?

I have one. Got it in 2013 (for Philmont). It failed several years later. The synmats don't have same guarantee as the heavier ones but after talking, they sent me another one. Still using it. Thought I really like the DLX9 I got around 2005. Fantastic! Bulky.

Arggghh! I just bought that like a month ago at regular price. Dangit.

So I got the Exped Ultra 3R and just used it on a 5 day trip. Couple things to note.

1st) It's fabric is a little loud. This was brought up in several reviews. But i'm not shooting for stealth so i didnt care. My wife said that its easy to hear though when i'm tossing around all night. Its like if you ran your finger nails across your winter jacket. That kinda noise.

2nd) It doesnt support you at all when you kneel onto it. Like if you are kneeling in the tent to get clothes on or move things around, it just bends and you hit the floor. Unlike Thermarest or something; those have a little cushion when you are kneeling on them still. So when you're laying completely on top the pad; thats when its at its best.

3rd) It sits a good 3 inches off the ground which is nice.

4th) Its nice and long and wide (i got the Medium Wide)for me. And i could probably have gotten away with a normal medium, but i like the space.

5th) Its incredibly light, packs easy, and the blow up bag is comes with is nice.

I will likely buy another for my wife. It was great to sleep on! In fact i gave it up for her because her back hurt so bad one night. And she improved a little after that night and the next. But other than the R rating; i think they're the same. I just never travel in the winter to need to go much better than 3R