Thermarest vs Montbell Sleeping Pads

Benjamin,
I have them both, the Pro3, the UL120, and a few others. The Pro3 and UL120 are equivalent in warmth, IMO. I suppose analytically speaking the UL should be a little higher R value since it's foam is solid and not waffled with holes.
The UL series of mats toggle to the pillow thus keeping it in place. That simple design feature makes a huge difference in comfort, keeping the concave pillow under my head so I can sleep through the night.
Also, the UL series is lighter than the equivalent Pro mat.

I've got both a prolite 3 and montbell 120 pad. It's hard to make a warmth comparison between the two since I've used them in different conditions but my very unscientific observation is that they are fairly similar in warmth and comfort. The prolite is die cut so is theoretically colder than the Montbell which has solid foam however the montbell is a bit thinner. Mine measures maybe 3/4 or slightly more thick. It's definately not a full 1 inch thick.

So warmth/comfort is pretty similiar between the two. With that said, I prefer the montbell pad for it's feature set:

1. It has the toggle system for attaching a pillow or foot pad without having them slip around.

2. The montbell pad seems less slippery on silnylon than the thermarest.

3. It has a built in strap for holding it closed when rolled up.

4. It's slightly lighter than the thermarest.

Not that you asked, but…

One alternative to a straight air pad to self-inflating pad switch is to get a 3/4-length self-inflating pad plus a blue foam section or two that you can velcro together at night. Chances are that your legs/feet won't need any air cushioning to be comfy — so this system will provide both weight savings and greater versatility — without any penalty to warmth or comfort!

The blue foam section(s) — being stiffer — provides for a better "virtual frame" if or when you use a frameless UL backpack. At camp, they do additional duty as seating pad and wind screen. And when it's time to turn in, you just velcro the pad sections together. Anyway, food for thought.

Don't underestimate this fantastic feature. I have the UL90, and with the MB pillow (and the way it attaches to the pad) , my life has changed…I used to use a travel pillow and wake up with it all over the place – no more. Plus, the MB pillow is quite large and the weight is…can't remember exactly, but I don't believe it's over 3 oz. This single feature would be enough for me to choose the MB over the Pro.

Thanks for the input everyone. Regarding the pillow, do you put the pillow on top of the pad (so your head is actually on pad + pillow), or above the pad (increasing the length of the overall setup)? If above the pad, is the pillow thick enough to be comfortable? I sleep on my side. I ask because if the pillow goes above the pad, I would get the 90cm pad, if the pillow goes on top, I would get the 120cm pad.

Tang- Just what I was thinking, going with a 3/4 length pad and some foam for my legs.

So it sounds like the pillow is actually comfortable? I tried the cheapo inflatable pillows sold on BPL and wasn't very impressed. Is there foam in the montbell pillow or just air?

At this point the only thing keeping me from going with the Montbell is that the local REI doesn't carry them. It would be nice to have the option of returning it easily if the pad isn't very comfortable (I'm spoiled by the Big Agnes now, and have bony hips).

Ben:

My set up is MB pillow (it's all air, no foam) velcroed onto my REI Lite Core short pad — plus blue foam to extend to 72-in length. I too am a side sleeper, and find this arrangement very comfy.

If you buy the MB pad, you'll have the option of anchoring the pillow on top of the pad — or laying it on the tent floor, but attached to the pad (i.e. lengthening it). This one is going to be subjective and you'll have to try it out yourself to be sure.

While I like the MB pillow/pad/toggle set up, I passed on the MB pad and opted for the REI Lite Core because of the added thickness (this pad has the same 1.5" thickness as the ProLite 4). For me anyway, I find the 1" thickiness of ProLite 3 still too uncomfortable. YMMV.