Alternatives to Mail.App on OS X

There’s a good amount of Mail.app alternatives for Mac OS X, and many of them are quite nice. Choosing the right one depends on what options you’re looking for in a mail client. There was a lot of hype about Letters.app in early 2010 that was headed by John Gruber. It was supposed to be the Mail.app killer for OS X but is now dissolved. The twitter account that Gruber supposedly took over still has almost 4000 followers but hasn’t tweeted since February. Either way, the linked article is a good read for anyone looking to switch or just wanting to know what else is out there.