I own & have used both. haven't used either in below freezing temps.
1. both excellent pads
2. both inflate well & can be slightly overpressurized by blowing into it w/o the valve leaking the overpressure while inflating it. (not sure if blowing into them is a good idea [moisture], especially if temps are below freezing. if anyone out there would care to educate me on this practice, please reply. many thanks.)
[Note: i had a prolite3 whose valve just vented most/all of the extra air if i tried to blow into the valve to slightly "over-pressurize" the pad. the proltie3 compressed much easier than either of the two pads you are interested in. way too soft, IMHO]
3. either would be a great choice, but...
even though the uber-lite is lighter (mine weighs just 8oz on my scale vs 11oz (11oz is NOT a typo) for the torso-lite.
I prefer the BMW/BPL Torso-Lite. Why?
first: my inflated torso-lite is slightly, but noticeably, firmer than my uber-lite. don't get me wrong, the torso-lite is NOT overly firm - it's the best self-inflating pad i've ever used.
second: basically, only one real complaint with the uber-lite (this may just be a personal pref. on my part; someone else may not mind & prefer to save the 2-3oz wt) the basic "hour-glass" shape of the uber-lite saves weight & is fine, but causes the valve position on the uber-lite to leave something to be desired. the self-inflating area forms a ~6" neck running from the valve, which is centered left-to-right on the top edge of the pad, down to the hour-glass shaped self-inflating area. this neck is narrow & unless one is using something for a pillow, even through my sleeping bag, i find this a bit uncomfortable since turning my head, left or right, causes my head to roll off of the narrow self-inflating neck onto the thin foam surface on either side of this "neck".
While the two pad's lengths are somewhat similar (the uber-lite is a bit longer), the uber-lite's inflatable "neck" causes the uber-lite to be effectively a shorter pad - about the same length as the torso-lite or even a tad shorter. The "neck" & hard inflation valve interfere with head positioning. I have an 18" torso for pack size purposes. With my buttocks on the pad, the back of my head rests on the self-inflating "neck". I could imagine that someone taller would have their head, and sleeping bag, resting right on the hard plastic inflation valve. Not sure if this is a good idea, having the sleeping bag "sandwiched" b/t one's relatively heavy head & the hard plastic valve, especially if the bag's outer material is a very light weight mat'l like in the WM Highlite. Would this, over time, damage the bag's outer mat'l??? Guess one would need to use something for a pillow & place it b/t the pad's hard plastic valve & the sleeping bag - not the best/normal place for a pillow IMHO - i would prefer a pillow inside of my sleeping bag instead of underneath it, though i rarely use a pillow..
If you are tall, then i think that you might need to use a pillow, or something to serve as a pillow, with the torso-lite b/c it might be too short to keep both your buttocks & your head on the pad. being quite short & having only an 18" torso length, this is not quite a problem for me, though it almost is. the back of my head just rests on the torso-lite when i position my buttocks on the pad. this is something that you should consider b/f purchasing one.
Hope this info helps. Any other questions I failed to address?
[Note: I mainly use a GossamerGear NightLight TorsoPad - much lighter, nicely forms a virtual frame in the ext. pad pocket of my GossamerGear G5 pack, i find it warm enough for 32deg & above.]