[jabo75]

Had our own exchange server, but could never get Activevesync Over The Air to work.
Moved all of our exchange accounts to The Message Center in December.

It's 10 bucks a month, but they give you the ability to downgrade accounts that don't need activesync and Outlook full accrees to 5/month for Outlook Web Access.
They also give you unlimited aliases and offer pop3 accounts for 3/mo.

Even though we are paying 200/mo now for email, we get 3 gig inboxes, 100% uptime, exceptionally fast email delivery, incredible (Postini) spam filtering, and we did not have to uprede our Server 2003 boxes.

Here's the coolest (and most pertinent to this post) part, Activesync works flawlessly. All calender, contacts, tasks and notes sync real time. Activesync preserves my inbox folder structure (I realize that some of the above options probably do that too, but certainly not all of them).
My battery drain is minimal because Active Sync only kicks on after the phone receives a hidden sms telling it to go get a new message, contact, appointment , task etc...

Last but not least, my phone almost ALWAYS gets the new email before my laptop (which) is always connected to the Exchange Server!