What’s the best email client for Mac?

I’m running OS X.6.8 with Rosetta and will continue to do so because I want to continue running some legacy programs.

One of those I have used since time began is Eudora. I've tried one or three other emailers, but I haven’t seen one that is half as good.

However, I'm thinking it is time to shift -- recently, I've had a number of mail boxes corrupt themselves. I back up weekly, so I've been able to make do bringing in the back-up mail boxes and losing up to a week's emails maximum, but sooner or later, I'm going to lose vital material.

So, sadly, I'm thinking of leaving Eudora behind, but where do I go? I love the way Eudora works, with multiple mail boxes in multiple folders, etc., its speedy downloading, easy direction of mail to various destinations, etc., etc.

Any suggestions?

Cheers, geoff
--
Geoffrey Heard
http://pngtimetraveller.blogspot.com/2011/10/return-to-karai-komana_31.html