I found that several applications would cause it to go crazy (lock up), including many Java applications and open office. Further, if you started adding many extensions, they would cause crashes (I'm sure it's because they were badly written, but I thought the whole point of haskell was no crashes).
So, if you find nowadays Java apps and openoffice work fine (or, you don't use them), and you are careful about which extensions you add, then you will probably be fine.