Ife see dspam is used with hash driver at the Moment.
I would recommend the following:
DSPAM as primary antispamfilter
Use with Mysql Driver instead of hash
Better preconfig of dspam itself
User based Configuration in the account
Groupbased Configuration on admin or domainadmin level.
With dspam its possible to have an absolute individual configuation of the Filter which is for Service Providers a must have. Its currently possible to set the most important Settings per User out of the Box.
Also things like spamtraps are possible and groupbased (for example domainbased) common trainings and spamtraps and config for spamtraps out of the ui which work awesome on dpsam
The current issues in Dspam (standalone) from my point of view are the quarantine box and the webui.
Both wont be needed in Zimbra since we have a Spam folder which used instead of quarantine and autodeletion after x days.
the webui is also not needed if those options (only a few mysql rows needed for that so not a real effort)
only groups are in an txt file
Rest will work out of the box and would solve a lot user whises i read here including of course my own :-)
That way every user can decided which kind of trainings, how agressive it should be, turn spam checkin off or not. which mails should be trained which not (user behaivior) if autowhitelist should be used or not
would be a big whish for me and a lot of other people - support by the dspam community is granted for such an implementation