Been a user of it for a couple of years now. (Admin is SEP).
Definately not as nice as Subversion, but miles better than VSS.
If you work 'offline', watch out for it not finding all your changes when you go back online - it ain't clever :-(
If you work 'online', it automatically checks files out all the time, which I find annoying - it's uneccessary FFS! Especially since (in VS) it 'helpfully' tells you if the file has changed since you got your copy, which tabs away from a more interesting panel (find in files, for example).
The only purpose of checking-out files (without locking) seems to be to show others how busy you are ;-)
Get the power tools.