The transfer process was extremely painless (at least on Hover's part). For some reason getting the authorization keys from GoDaddy was like pulling teeth. After requesting the transfer keys it took hours to receive the keys by email. It was also no picnic getting domains I bought through Google Apps transferred since each domain lived in it's own account at GoDaddy or Enom.
Hover has been generally awesome. The first time I had to call them for support I was shocked. No phone tree to get to a human. A human picked up the phone in two rings. They were super helpful fixing an issue I ran into transferring a few domains. When I checked my credit card statement today I noticed that they accidentally double-billed me for the domains that I had this trouble with. I sent them an email and within 4 hours (on a Sunday) had a response that they were going to credit me back. Their Twitter account has also been very responsive about web site suggestions.
The Hover website is great. Buying and transferring domains is a piece of cake and there aren't 150 up-sell items that assault you on your way to checkout. If you have domains you want to move or are thinking of buying a new domain I highly recommend Hover.
P.S. I also took the opportunity to move my blog to blog.jamesbogosian.com.