Mittens here too, unless it's really warm (like spring skiing warm).
I think I have mild Reynaud's syndrome. I've found that even if the rest of my body is so warm I'm sweating, my hands can still get freezing (and painfully) cold. And I always wear a helmet with a liner underneath, so it's not like my head is cold. This is especially true if we're hiking or out touring, which is extra weird. Like the more my blood is going to my legs and lungs to exercise, the less goes to my hands and toes. And then, like the switch gets flipped, sometimes they warm up all of the sudden and are hot. But some days they never warm up, even with disposable heaters in my mittens.
I understand the logic that gloves are nice for more articulation, but I've just never found a pair warm enough, and I can't think of many things that require more than a thumb and finger to do. I usually wear a liner glove under my mittens, so if they have to come off, I have something on that lets me do what I need to do and then put the mittens back on.
I've also gone to mittens with the longest gauntlet I can find (about halfway to my elbows) to keep the drafts out from my wrists. I think that helps a bunch. And I use disposable heater packs in there on the colder days. (I usually buy a case or so when I can find them on sale). That way, I figure that even if my circulation cuts itself off to my hands it's NOT freezing in my mittens and hopefully I won't get frostbite even when I can't feel my fingers - which is most of the time. Half of the time in winter I can sit on the sofa with big wool socks and comforters and stuff and have feet and hands that are like ice.
My husband will wear thin spring gloves all winter and whine about how sweaty his hands are on the lift. It's just not fair.