Well, my frustration with the speed of Mailwasher prompted me to check out a few possible alternatives to handling spam. I saw a great review of Spam Inspector which integrates right into your e-mail client, works as a proxy between the server and the e-mail software (so no spam sneak through) and has one of the best Bayesian filters available giving it top accuracy once it completes its learning phase.
My main reason for trying others was to decrease the time it takes for me to get my e-mail. Alas, Spam Inspector (and the others I tried) were no faster at processing than Mailwasher. Process-wise, I really like Mailwasher and it does exactly what I want, so there’s no worth in changing and having to redo the filtering rules that I’ve developed over time for Mailwasher.