Reasons for me not to give it a try:
- Rule based mostly (which I think of as 'SA')
- No db support, as far as I could tell. My dspam keeps everything in a postgresql db and I can easily backup/restore that with all my other stuff (dovecot/postfix virtual users, for example)
- ~Easy~ to integrate into anything. Look for 'how can I make dovecot-antispam integrate with dspam' and that's been done a thousand times (and works nicely). I haven't found a decent number of rspam resources
That said: My whole post basically says that I didn't try it (for reasons that were important to me). Their site looks interesting and in the end I guess I'd love to hear about successful dspam->rspam migrations as well.