I finally was able to test the base pro pants and shirt this winter and man what an incredible combo. I took these winter camping with me and wore a regular layer over them (cargo pants and a light sweater).
It was 30 degrees and I was driving with the windows down lol (Keep in mind I get cold easily). I arrived to the campsite and was keeping semi active, cutting timber and setting up camp but stayed warm the whole time with just these two layers on. I actually was able to take off my gloves which I can usually never do because my hands get cold so easily.
Sleeping bag temp was perfect just wearing the base layer. Was actually too warm trying to keep my sweater on (This was about 10 degrees F at this point). Just in the tent and outside of the bag, it was pretty bearable with just the base layer on. Maybe a blanket or my shell layer would of been needed if I wanted to stay out of my sleeping bag for a while.
So yeah, I would go ahead and buy these if you are on the edge of deciding. They pretty much kept me warm until the temperature dropped and the wind started to pick up. I probably could of continued the night with just these on and a wind proof layer.