Hi
I've just got back from a trip to Peru which included a 7 day trek around a glacier - my Helium 200 was fantastic even when it was -10c outside (there was frost on both sides of the outer most nights, and on the inside of the inner above my head one night, presumably from my breath!).
I appreciated the "2 man" nature of the tent as it meant I could have my kit bag next to me inside the tent and hence have liquid water in the morning... until I took it out of the tent in the morning when it started to freeze!
I had the warmest tent of our group by a long way! Other folk complained of frozen sleeping bags while I was all toasty in my alpkit bag. When used in England before I left it was a little too warm though as there's no ventilation other than the door.
The provided pegs didn't make it though, I swapped them for some aluminium spikes.
My first Helium got returned due to the pole starting to tear after a couple of uses though, so do check the poles carefully!