Andy,
the schwalbe's are carbide studs so they should last a while. At least two seasons so they say.
However, I haven't tried them. I ordered Nokians for my Kogswell in 650b, but alas they will not be sold in the US until next season.
I might buy some Nokian A10's (32mm) in 700c for my fixed Miyata. They are available this year.
The fixie crowd seems to argue that fixies are pretty decent on ice because of the more direct connection to the drive train.
$38/tire ? hmm... might give it a whirl.
-GB