I've been a long-time FastMail user, and they make me happy. For various reasons I never liked using Gmail, although I never tried Google Apps for Domains. Max Masnick recently wrote a post on his move from Gmail to FastMail and experience is close to mine - and his migration tips are useful for all, not just Gmail users.
If you're looking for a fast, sturdy, secure, easy-to-use third party mail service for yourself, your family, or your business, I can highly recommend FastMail.