I’ve been pretty happy with Apple Mail, which I use on my Mac for a few personal email accounts (including an iCloud account and a Gmail account). However some things just annoy me with it. Compared to Gmail and other email providers, sometimes the flexibility is lacking or it just doesn’t work the way you think it should. It also might be my imagination, but it seems to be running slower with my large email amount than it has in the past. So I stumbled across another email program for the Mac called “Sparrow”. So far, it’s worked amazingly with both my iCloud account and my Gmail account. It’s very fast and responsive and has some things that seem easier to do in my opinion compared to Apple Mail. If Apple Mail is getting you a little irritated, I’d suggest taking a look at Sparrow.
They have a “free”, ad support version, or a paid version which costs $9.95.
One thing to note, they don’t support Microsoft Exchange accounts like Apple Mail does. So if you need Exchange support, you’ll need to stick with Apple Mail or Microsoft Office 2011.