Regarding traction, I have had a very good experience with my Reva. As long as you have the winter tires on, it goes anywhere.

Regarding battery performance in the winter, my experience last winter was disappointing. If the car is left unplugged in the winter (even for 30 mins), the batteries can become seriously crippled. Therefore, one must plug-in every time the car is idle. Unfortunately, this will reduce the lifetime of the batteries significantly, as battery life is given by the number of charge cycles. In the winter, I have to spend a charge cycle even when the batteries are half-full.

The Reva should have a setting whereby the battery does not charge -- only heats up -- when plugged in. This would be so easy to implement!