I too just got the MPx220 last week. I love it and have it syncing automatically to the exchange server here at work.. Amazing how easy it was to setup with exchange 2003 and always up to date notifications. I have received emails while out of the office and replied making people think that I was at my desk, only to have them find out my office is dark and I was at home or had the day off.
Have you tried to connect your X50v to it to connect to the internet. I can't get mine to complete the pairing operation and have also tried it with a V505, which didn't work either. Dell is sending me a replacement unit today. See my post here:
http://www.aximsite.com/boards/showthread.php?t=61702. I would be interested is hearing if yours works.
Enjoy the new phone! I know I am.