I switched to Dynadot and havent had a bad experience. Their interface is simple, quick, and clean. The pricing makes sense, and their people are friendly and helpful. YMMV.
I registered a domain with them yesterday - but have separate hosting, so don't need to buy more of it from them. I'm unable to do anything beyond change DNS servers (no custom mx records, for example).
When I contact their support about something, it usually gets a prompt (within 10 minutes) response. But when it deals ith deleting domains, they take forever to respond. And they refuse to let you delete/cancel a domain. Even though ICANN's policy lets you do so for 5 days with the grace period. Since the ICANN still hasn't changed the policy AFAIK.