My only gripe with how it is on my PC monitor - still a semi-transparent text of "IM Mailbox" and other text below it, which interferes with my typing replies and the like. Its not a big deal really just a little irritating and means I have to undergo the agony of scrolling up/down a bit to see what I am typing
It's not really a problem to be honest.
It interferes a little with replying to posts that's all. If it was moved over to the left side of the screen it would be better for replying to posts. It's just a preference thing really so no big deal.