On a quite busy e-mail server (2003R2 sp2, runs no other services on this machine) we installed v3.0.566 and experienced a lot of random kernel errors. After uninstalling v3 and reverting back to v2.70.39 the problems went away.
I noticed that a new version was just released in July (3.0.669) - would you consider this release to be stable when port activity is heavy - or are there good reasons to stick with v2.70?
Ports heavily used are: 25,26,53,110,143 with a lot of socket connections.
cheers / Peter