Hmm, I was using it fairly heavily while going through a book which required loads of messing with graphs last year for a month maybe and I don't remember it acting up... Perhaps I got lucky? Is it known to be buggy, in general?
It's so bad that the university I "loosely associate" with have their own patched version to fix a load of problems with it.
This makes communication, which is a really big part of mathematics, extremely difficult.