The only thing I've noticed with the extra-knobby studded tires is that they start getting a little squirrely around 15MPH. That is, the bike begins to feel "loose" in the steering department. (On dry pavement, which is bad for studs anyway so I try to go slow or avoid it if possible.)

I wouldn't characterize it as a dangerous feeling. I wouldn't want to bomb down a hill either, I don't think.

I'm done commuting until after the holidays. Hopefully this warm weather melts a lot of the trail snow so it smooths out.