I have the 210 on our 04 A4 1.8TQ Avant and the M3 on my 97 328i. With two winters on the 210s and one on the M3s I think I like the M3 a bit better in the wet and dry. Snow is hard to compare as the Audi trashes the bimmer in the snow (duh). Overall, I don't think you can go wrong with either, but I'd probably lean a bit towards the M3.