I use Under Armour long johns, then $20.00 Fleece I bought at Sportsmans Warehouse (clearance). Pryor to that I had some cheapo fleece from Wally World that kept me warm until it fell apart after a few trips.
In extreme cold I wear the Under Armour, then a pair of cotton, yes I said cotton, long johns over that. Followed by the Fleece. Make sure the synthetic material is on first as it whicks the moisture away from your skin.



Last winter was brutally cold on the Frying Pan river. This pic was taken at -10. The average (first thing in the morning) temp was -5. I never had issues except at times I thought my fingers were going to fall off, or that it felt like my nose and ears were on fire.

Just my opinion.