I have had surprisingly good results with a slightly oversized pair of
North Face Canyonwall gloves plus a set of fleece glove liners. This after having mediocre-to-poor luck with heavy ski gauntlets and insulated work gloves.
I think a key advantage to this configuration is that it provides meaningful insulation on the gripping areas of your hands and fingers, so they're protected from the cold metal, plastic, and rubber of your handlebars and brake levers.
That said, I haven't tried any of the purpose-built winter cycling gloves/mitts. Most of the ones I've been able to find temperature ratings for have been...inadequate.