I have managed our Email and Web server since 1994.
I basically found myself spending more time trying to keep up w/ the massive volume of spam.
My time is valuable! I keep fine tuning server to cope with 2300+ simultanious smtp sessions. My colocation provider can't figure out how to configure their switch and want to bill me for their time to investigate.
I'm just fed up with wasting my time.
So far Google Apps has worked really well!
The import mail function was seemless and imported my 50K+ emails and 100s of IMAP folders (as labels).
Now I can focus on managing the shopping cart and business development!
My only concern about using Google Apps is data backup.
If anyone reading knows of a way to backup mail from Google Apps, let me know!
Jason