I've been testing Dotster for the past year. Always have been with Network Solutions before that. My main reason for leaving them was money (Dotster is way cheaper), but the reasons for me to move all my domains to Dotster completely (did so last week) are:
- better and faster customer support
- better control panel for managing your domains
- much (MUCH) less cumbersome domain editing (info, dns etc.)
- cheaper
I have no experience with others though, but Dotster is so satisfying that I don't feel the need to look for another
