I'm planing to move to fastmail.fm in the near future. I find the Gmail UI very sluggish and quite the opposite of being user friendly, and I also don't have any guarantee I won't become a horror story about how Google automatically shut down my account without me doing anything wrong.
The FastMail UI is the best webmail interface I have used. It has keybindings for just about everything, and the UI is snappy and intuitive. Did I mention it doesn't hit me up to join Google+ or give it my mobile?
Moving to FastMail from GMail for personal emails, and self-hosted (via Thunderbird) for business emails, has been nothing but a pleasure.
Fastmail reworked their UI recently as well (shortly after the Opera takeover I think). I preferred the old UI which hadn't really changed in years, but the new one isn't too bad. I do 90% of my email in Emacs though, and only use a browser when I'm on a platform where I don't have ssh.
