I've been using "lobster mitts" for over 15 years commuting and trail riding in the Chicago area. These are good down to at least minus 20 Fahrenheit. I've had 2 or 3 pairs over the last 15 years. I finally found a pair that has "Hi-Vis" coloring; previous pairs were mostly black with reflective elements.
It's easy to operate trigger-shifters with these mitts; STI shifters are somewhat less easy to work, but can be used. My experience with twist-grips is not as good, but that may be because the detents on the shifters I've used were not strong enough to make the gear positions obvious.
Steve