I can use my own domain too. It's pretty great. The web interface is simple but it has improved immensely since I've started to use it.
I guess this is the missing piece. One thing I miss from gmail is its ability to automatically sort incoming email into categories, even if you don't have filters. Fastmail has all the classic filters, but they do not apply to existing emails, which is a major hassle. I've been using Sanebox to keep it less insane, but I don't like giving access to third parties.
I guess I'll play with this thing and write something to organize my inbox.