I've done this event several times and it is a great time.
Portions of the course are on fire roads and these sections are FAST (I take the bash guard off my Mountain Bike and re-install the big ring just for these sections of the course). Portions of the course are on smooth, flowy singletrack and these sections are just plain FUN. But every so often you'll hit a technical section requiring some handling skills. This is where you can tell the guys who ride road most of the time vs. the guys who ride mountain...
You will want a Mountain Bike for this event.
I'll be back again this year with the guys from last year, so no interest in putting together a team from me.