I have used ISPConfig for the last few years, abandoning another useless commercial product that shall remain nameless but ends in esk! Props to the devs, it is an excellent product, and it doesn't break when you upgrade - even better! One area that I am sure everyone agrees could be better though is spam training. Spamassassin is good there is no doubt, what about also having razor and dcc for detection as well? Another thing I have just come across, and will try installing and config'ing is Ian Douglas' Spamassassin-trainer What do you all think? Should this trainer be included in the default ISPConfig build?
Trainer! Definitely! Spam being the ever growing pain it is, the more tools the better. Especially if they can be turned off and on per domain and user.