I've been using this for 10 years at least. It solved and keeps solving having to deal with the seemingly never ending spam flood on multiple accounts. Still I have 99.4% accuracy, from the beginning in PowerMail and since quite a few years in Apple Mail.
I've never had a serious problem as it has mostly just kept working and that includes the betas. For the odd issue support has been stellar. I'm still impressed with the great service this app and its maker give me still after a decade. There are not a lot of apps in any category I can say that about.