Ask HN: Desktop mail client with good rule setting and filtering

I've been using the new Outlook for some time now, and many of the redeeming qualities of its predecessor are gone while its negatives remain or, in some respects, have been exacerbated. While the new client is betaware at this time, the prospects for meaningful improvement in a reasonable period of time are dim.

My one great need has been rule-settling and filtering. I get hundreds of emails a week, and, while Outlook isn't superb, it's the best of the ones I've tried (Thunderbird, Claws, etc.). If there is a client that can sort every message received into folders by sender and all in a few lines of code, I would greatly appreciate being informed of it.