I have been on a quest for the perfect winter cycling gloves, and the Castelli Boa may be the best I have tried. Other waterproof/breathable gloves can be very difficult to put back on after taking them off, since the opening is small and the lining is separate from the waterproof/breathable membrane (looking at you, Gore-tex and Hipora) Castelli addresses this by using the excellent OutDry membrane, which is bonded to the shell an lining and feels like a single layer of material, and with the Boa closure. The wrist of these gloves opens wide, and then cinches down for a very trim fit.
I have worn them on a couple of rides now, both road and trail, in temperatures down to the low 30s. I have honestly not thought much about the comfort of my hands while I have been riding. They feel neither too warm or too cold. When it comes time to take off the gloves to take a photo or eat a snack, the ordeal I've experienced with other gloves is a distant memory.
I usually wear gloves in either large or XL, and I got these in XL, as I don't want winter gloves that are too tight. Thumb and middle fingers are perfect, other fingers are a tad long, but the function of the glove is unaffected. I expect I could fit a thin liner underneath for sub-freezing temps.
Castelli has a thin laser-cut cuff on most of their jackets, which slides under the long gauntlet of the Boa glove exceptionally well. Wrist gap is a thing of the past!
I'm the Castelli Brand Ambassador for Competitive Cyclist and Backcountry. If you have questions about Castelli or other winter cycling clothing, call me at 801-736-6396 x 4076 or email me at firstname.lastname@example.org