For a while now I have been researching a variety of different open source email servers to replace my worn out exchange 2000. I've narrowed my options down to 2; DeskNow & Citadel. Both seem to be easy to work with and with the features they have are strong candidates to replace my exchange box. A quick google search will give you plenty of reviews for Citadel, but I have yet to find any for DeskNow.

My current plan is to grab a spare box and start playing with each of them, decide on one, move it to better hardware, then migrate my user base to it.

I've never migrated off of exchange before so I don't know exactly what I'm getting myself involved in. So I need some advise:

Have you worked with Citadel or DeskNow? What are your thoughts about them?

Have you migrated off of exchange, if so how did you do this and what issues did you have to overcome?

Have you any other advise for me?

Thanks!

You haven't really explained your requirements. Are you after a mail server or full groupware server?

I have no requirements to post. I'm not asking for suggestions on what to replace exchange with, I'm asking about migration. I want to know what challenges you had to face while migrating from exchange, what you did to over come them, how you migrated from exchange, and any other helpful information.