The neoprene gloves do get quite sweaty. If you need to take them off mid-ride, they can be a pain to get back on.
However, I get really code extremities, and I find my Castelli Diluvios fine down to 0°C on their own.
When it’s *really* cold I stuck a pair of These over the top. It’s a bit hit and miss to change gear (road sti) but braking is fine. These Phew Lobster Outers look like they might be a better bet if dexterity is required.
The key thing with that setup is that the outer is a bit loose, so keeps the wind-chill off the main insulating part of the glove.
Another thing that really draws the heat out of your fingers is resting them on metal brake levers.