I use backset quester and am pretty happy with it. My only complaint is that occasionally it seems to get out of sync a little bit and scares me (thinking that I forgot to pickup a quest on one of my slaves), but that's pretty rare, most of the time it works great.

The main thing I like about it is I can quickly glance at it and make sure that everybody has the same quests, and that they are all at the same place on said quest.

I bind mine to a key and just toggle it off and on so I can see more quests at once.