We just migrated from GoDaddy to Bluehost. Simultaneously, we migrated from OSC to Zen. We had done testing on GoDaddy, and to say the least, the configuration was complex and fraught with potential pitfalls... also the page parsing performance was very poor.
Total downtime for us was about 25 minutes due to the nameservers being rerouted. GoDaddy was the bottleneck throughout the process. I was able to FTP down our site from GoDaddy in about 45 minutes, while loading a Zen store up to BH that was more than 2X the size wen in about 15 minutes.
We had numerous problems with GoDaddy. Too many to mention. First few weeks with a new host have been a dream comparatively.
GoDaddy seemed cheap in the beginning, but after all of the additional work and all of the crap we dealt with, it was many times more expensive.
Simply said, their servers are overloaded, their support is not knowledgeable, and internal communication is poor. They are a sales-oriented organization, not operationally-oriented. We needed an operationally-oriented host with reasonable prices. We got that by leaving GoDaddy.