Martin Brown wrote:

I will add my vote for Thunderbird too. And just to point out that
although its filtering is not full regex like TP it is able to add
custom header fields and apply global kill rules across all newsgroups
(something which TP notably lacked). I do miss regex and would urge any
TB users to request it to move the regex match feature up the wishlist.

I like Thunderbird but found it occasionally displayed duplicate posts
so, being an Apple Macman, I purchased MacSOUP which has no bells or
whistles but is fast and reliable and is great for offline viewing.

--
The ex-Meteorologist formerly known as Purbeckview