Quick question,
Outlook users in our environment often will get "chucks" of emails, groupings all at once, every 10 minutes or so instead of real time, or a minute or two delay. Exchange and Outlook should be notifying each other of changes every 30 seconds or so from what I know.
Some FYIs: We connect to our Exchange Server over a couple of tunneled linked T1s, on a different colo'd subnet. this is the only issue we are experiencing at this time.