I found a pair of black fleece flip-mits (glomits) at Yeagers in November. With a pair of polypro liners underneath, they are almost winning a winter riding combo. However, these glomits are of rather odd dimentions. They are long enough for my hands but are quite floppy around my fingers and the mit is a bit too baggy. These are not bad, but I do find they tend to catch on brake levers.
The part I clearly didnt like was the elastic around the wrist. This collar was too tight, and with the tighter fitting pair of polypro liners I prefer under them, it was actually making my hands colder. Why? It was pinching the circulation around my wrists. You need free circulation in your hands and feet too keep them warm.
I went at them with a pair of scissors this week and cut gaps in the wrist elastic so that the elastic would not press so tightly on my wrists. It looks trampy, but I definitely see improvement! On a 45 min ride to work in 28F weather, by the time I got to work, my polypro liners were damp with sweat.