I bought the Marathon Winters too, the day after the first snowfall (never ridden in winter before). I've posted a few times back when I was having lots of fun on the icy shortcuts and the skateway, but now that I've repaired my SS roadbike, I think the charm is wearing off.
I've switched from a pair of 200 stud tires and 45 gear inches (on average) to 25mm slicks and single speed at 70 gear inches and I'm instantly happier. I fell a LOT riding on the Marathon Winters. Dozens of times. It's easy to push them too hard on ice, but I'm not gonna complain about that, I was playing around. But like a previous poster said, they're crap in snow. I've never skipped a day because of the weather, and I'm pretty sure I'd rather take my chances with the ice than put up with the sliding and fishtailing (and sheer effort!) of riding in the snow. Skinny road tires cut down well enough to at least have some lateral traction, although I'm hoping for at least one more snow storm this year to come up with a good judgement.
I think in the future I'll be saving the studs for the black ice and freezing rain days, when WALKING is dangerous. For the rest, I'll take the dramatically faster road tires that can actually handle snow (heavy and light), skip the icy/hardpack shortcuts and use my better judgement to avoid ice hazards.