Nice for its ready-to-use list of stuff to backup, like preferences, libraries and mail folder. Its interface makes it really easy to backup important things even for those who never dig inside the system.

But if you use it professionally it shows some flaws.
As many have already stated, it lacks the possibility to define multiple backup profiles, and on production machines it's quite important to define different profiles for different files or clients.
Then, I really don't like the fact that during the backup the feedback is so scarce it's almost unuseful: I don't know which file or folder it's checking (only in a superficial way) and most of all I have no way to understand how much time it will get. And if your backup is many gigas, it's not an option... believe me!
And it's even worse if you consider that this app is processor intensive and it's not easy to stop since most of the time you have to hit the cancel button repeatitly (and I work on a G5DP).
So do your backups only when your mac is idle or you'll get frustrated trying to do something else at the same time.

IMO, it's a very good and easy to use backup utility for the home user, for it's iphoto or itunes libraries... but for professional users you can find better options, even in the freeware.
SilverKeeper, for example.