I've been on one trip. Lows in low teens. Gloves worked great. Even when I knew my hands were perspiring from high energy hiking, they were dry. The moisture moved out and away from my fingers. The shells are breathable supplex, and I think the fleece is 300wt.
Mods: I added a cord lock system around the wrist and I have cut 2" off the length of the fleece...the fleece was banging up against my jacket. I am going to sew the locks down to the mitt, so I can adjust them with gloves on and I have added a small strip of Velcro to keep the layers together.
I hang the gloves on a strap, so I can let them go to do chores with my fingerless gloves, but can don them quickly when the chill comes.
I'm sure there are commercial setups available, but at the prices I saw...I can make a bunch of these.