Now that the temperature is pretty much above freezing, I'm looking back and thinking my rides under 20F were less than fun. Below zero was unpleasant. Riding in 6" of half-frozen, rutted, snow/slush mix was not so much an adventure as a pain.

Next winter I'll probably do it again, but right now I'm finding 70F remarkably nice. Which maybe is the major benefit of the suffering part.