When I try to reply to a message, Outlook hangs, I get a "program not responding" and then after about 30 seconds or so the message shows up on my screen so I can reply. It seems like after it has done this for the first two or three messages, it opens others quite quickly. But then I can open a few more and each one hangs again. And if I leave the program for a while to do other things, when I return it hangs on reply again. (Oh, and this isn't when I first turn on the computer or Outlook, so I don't think it's a "not yet connected" problem.) As you can understand, this makes the program pretty difficult to use.
Oh, and I should mention that when I access my email using the web exchange, reply opens the messages instantly.