my shitty jacket doesn't have wrist gaiters or thumb loops. In powder, snow gets in my gloves if I wear them under. I agree, though, gauntlets over the sleeve look really dorky, but it works better for me in pow, so that's what I do....but only in pow
I have both. Aesthetically, the under gloves look better. I find that both are easy to put on. If I'm riding with my over gloves (mitts) I cinch down my jacket cuffs tight and the gaunlet slides right over everytime.