Trousers aimed at walking and backpacking, but versatile enough for climbing and mountaineering too, Montane's Tenacity range has an option for every season. Xa White and Dan Bailey road test them all.
Seems like these are an update for the Terra. I'm a bit gutted, Montane Terra were the only trousers (outdoor brand or other) that actually fit me. Judging by the description these appear to have gone the way of every other brand and become "slim fit" which usually results in me having to get about 38 inch waste to get my legs in them.
Like you say, the Tenacity XT's are an updated version of the Terra Mission trousers, but for what it's worth I didn't find the fit of the XT's to be particularly slim in the legs - although I don't have a pair of Terra's to compare them to!
I was more referring to the regular Terras. The mission are like most modern trousers and I have to size up and really pull the belt in tight. I might have to stock up on Terras, hopefully they will all be heavily discounted now.