I've been using these gloves daily since I bought them. Temps have ranged from mid 40F to 0F ambient. Above freezing, they are great on the own. Below freezing, I've been using them in conjunction with some pogies. They have a good feel for brifter use, easy enough to use a computer or Di2 system, and perfect for daily winter use.
The one complaint I have is that the wrist zipper is designed for use on a thin jersey layer and doesn't do bulkier layers as well. So if you're planning on wearing them to the outside of a jacket to seal a wind entrance, they might be tight.
We'll see how well they hold up. After blowing through 2 pairs last season, I'm hoping they do better. Construction is solid, having some extra protection on the thumb area for hood riding is clutch, and the material seems to be holding up against daily use and weekly cleaning.
The zipper opening is a novel concept that makes the gloves easy to get on and off, even if your hands are sweaty. I had hoped that the Spettacolo RoS gloves would be able to keep my hands warm down to freezing temperatures but they fall a bit short of that-they are fine down to about 40 degrees F or possibly a couple of degrees lower but no more than that (at least for me). They are not too bulky, allowing for accurate shifting even with electronic shifters. However, sizing does run a little large as I have worn size large in previous Castelli gloves and I required a size medium in this model. Overall, a good addition to the Castelli line of gloves.
Tried it during my early morning training at 34.8 degrees weather. Thought it would get cold and sweaty but it held up after my 84 mile ride. Usually my hands would be freezing cold because of the humidity in Florida with the cold temp, but it didn't. However, towards the end of my ride it started to get colder. Maybe it's because the dew of the humidity was creeping its way into the gloves. Anyway, so far it held up pretty well, especially with the riding temps at 34.8 at the lowest. Only issue was the zipper not fully zipped all the way up, but never unzipped.
This is a great pair of gloves. I like how they go up the arm a little to help keep the cold air out. I was using them in the cold weather, mid 30's temp outside, and my hand were very worm the whole time.