1. I use Exchange daily on my device so I just typed in my server information and my domain information and I was on my way. The only Exchange feature it seems to be missing is Search, but everything else as far as I need it can do.
2. There is no true push support for POP3 and IMAP unless the IMAP server supports IMAPidle, which most don't right now. On your DROID only GMail and Exchange email will be push.
I use exchange too and it has been great right out of the box. Push works great for email and calendar. I dont use the exchange contacts because I dont need all the contacts on my exchange server but those push as well