Remember this is a Release Candidate (ever wondered what the "RC" meant? Well now you know). So there may be some bugs, but think of it this way; Microsoft release beta software all the time, never tell you and it's buggy. At least Mozilla are putting their hand up and saying "we want people to test this before we call it production ready" - and they're NOT charging you for the final version once they get it right! Way to go Mozilla!!