One compatibility issue relates to Norton and IE9 and above. No matter what I do, I cannot enable the Norton Toolbar. This does not relate specifically to the beta version because it was the same in NIS 2013 that I used before testing started. Reading various help forums it seems to be an issue with IE's protected mode that insists on 64 bit operation, but I had hoped that Norton had developed a workaround by now. I can enable the toolbar in IE8 though.
I switched to Chrome a while ago for this very reason, but there are occasions when I prefer IE.