For everyone that really loved the old style zion pant, i have good news that the sitka territory pant is (in my opinion) a step up. Superb stretch, ultra comfortable, same size fits me better in the territory than the zion. Only negative i could see right off the bat was the lack of the zippered cargo pocket which i use as a phone holder when flying. However, the pockets on the territory are robust (2 open front, 2 open rear, plus a zippered rear and a side “phone” pocket that is too small to fit a phone) and both side pockets have a reinforced area for hanging a clip knife on or something similar.
I can not speak to the breathability or durability as i just got them, but the fabric is quieter in the territory and it feels like it should breathe just as well as the zions. I wear my zions when doing all sorts of activity outside, so I will give the territory pants a run and see how they hold up.
I know the price point is slighter higher, but if you can find the territory pant on sale or have a discount to use, they are going to be a formidable competitor to the prana zion .