In reply to chrisholl24: I haven't actually used either of these trousers but I was shopping for a new pair of winter softshell trousers last week. I tried on the Gamma MX pants but opted to not get them as they were too insulated for me. I prefer to have the option of putting on tights underneath. As all of my climbing will be in Scotland, I thought I might overheat on the walk in in the Gamma MX. I do have a couple of other pairs of Arc'teryx Gamma pants though. The LT pants are amazing and the outer is really water resistant. If you treat them every now and then they are not far off waterproof. If you have the cash and are ok with lined trousers like the Gamma MX I would recommend them. I expect if you were using them for higher altitude stuff, they would be pretty unbeatable.
I ended up getting ME G2 Ultimate Mountain pants if that helps?! Tiso had them in the sale..