The qt (quote) tags are bugged and really don't work properly.
Many times, you use qt and /qt - and end up with quoted text that won't sit in it's 'quote box'. Makes it difficult to read who's saying what, if you've gone to the trouble of responding to a copule of people in a single post.
It would be good to be able to select a block of text, and hit a 'quote' shortcut in the button bar too - to have the software automatically add the tags. Phpbb forums all have this. I don't think anyone would miss the subscript/superscript shortcuts if space needed finding.