My experience of Zoneedit.com
Don't use. I made a blog post around six months ago sort of praising them and while I haven't really kept up with the promises of having an active blog - i.e. at least a few posts a week I do have a website I want to keep alive. Zoneedit.com are managing my DNS as a way to bypass the premium service charged by uk2.net just so I can get tumblr to use my domain adamgarretty.com.
Zoneedit have been down several times in the last six months when I've noticed and probably even more than when I haven't. Their user interface isn't very easy for the layman and for me it's just another link to go wrong. Once I notice its normally around 24 hours before it's back up, if I was a super-blogger-who-relies-upon-zoneedit-to-make-a-living-guy then I'd be pissed, luckily I'm not.
The solution I've come up with is to eventually move everything including the domain to hostgator for the relaunch of adamgarretty.com. Hostgator hasn't been chosen out of any weighing up pros and cons of all hosting possibilities, but out of easy logistics for the person who is creating the new website. As always, do your research when you're looking into hosting - some are worse than others, some have features others don't have, jumping into the nearest convenience can cause future headaches is the lesson.
Additional: Site down again. Zoneedit are no longer part of my life. Temporary solution that includes a banner using webdiversion. Very unprofessional.