I've used Evolution as my primary email client with both uw-imap and google's imap servers. Works great for me. I also have 60+ users using it for pop3. I'm surprised at all the negativity in this thread. We don't use Exchange. So I can't comment on that.
I enjoy its integration with the Gnome desktop and find that Evolution/Epiphany are a substantial win for memory consumption compared to Thunderbird/Firefox on my Gnome desktops.