Recently I figured that my spamasassin setup stopped working correctly for some reason. At first I didn't see that, then I didn't care immediately as Thunderbird ist still 99% right, but when using Roundcube while "Thunderbird at home" is shut down, it became more and more annoying. I rechecked my setup twice, started all over, re-trained it for almost a week, to no dice.
So I watched out for alternatives. DSPAM. There is nothing else, really. To say one thing upfront: it works from the start, even while being in training phase still.