Hmm. The only problems I've had so far was trying to apt-get install Konverse, which in turn wanted kdelibs3, which in turn caused apt-get to uninstall a large chunk of KDE.

Whoops.

Obivously I recovered, but it was a bit unexpected to say the least. From what I've been able to find out about the matter it looks like unstable has some dodgy dependancies.

Don't take my word for it - go hunting for answers of your own.