I bought a pair of bottoms this fall. I have been rather impressed with them. I used them as a single layer under my wools on "warmer" cold days (around 30 +/-) and with long johns on colder days. I'm a big dude and I thought the 3xl were very comfortable, snug, but comfortable. I wanted to get the top but the 3xl felt tighter and more constrictive so I didn't get them. (i'll lose a little more weight by next year and get a pair) the only complaint i have with the bottoms is they have no fly! It can be hard digging everything out of several layers, especially on a cold day!!
ps - i have cabelas brand "silkies" and Bass Pro "polartec" medium weight top and was pleased with them as well