There are many various categories with various distances
(e.g. children, youth, families) but I assume you're interested in the main single runner categories which are 8.6km.

These are:
Elite (invitation only!)
Züri Fit (<40mins)
Premium (<48mins)
Medium (48-55 mins)

If you expect to take longer than 55mins you'll be signing up with the "fun-runners" in their Faschnacht costumes.

Due to the large amount of participants the start can be a bit like the pamplona bull run, but that's all part of the fun.

BTW you only have until the 25th Nov to sign up!