This is my hand at five degrees. It is warm.
That information is a review by itself, but I'll share some more details. I've used Neoprene gloves a lot. I like them. If they're designed correctly they have any amazing amount of warmth, minimum bulk and a fair temperature range.
Most cycling winter gloves are pretty similar to ski gloves; usually some kind of insulation like Thinsulate to create loft. The trade off is usually that bulky feel of the loft for the warmth. Neoprene packs a lot of insulation in 2mm. The brushed lining of Glacier Outdoor's Premium Cycling Glove gives the inside a nice, non-sweaty feel. Yes, your hands will sweat in gloves of this construction IF you miscall the temperature range. But these are windproof, so unlike a wet hand in conventional glove, you still stay warm.
Another obvious plus to this glove for those that love CX is that waterproofness. Fall down in the snow? No problem. Get these for the upcoming Winter Races. Nationals in Boulder? Yes.
We've got three other gloves for lighter conditions that we've been field testing too.