The biggest source of pain moving forward is going to be the projects that haven't transitioned, including the various command-line tools that work on parsing, generating and manipulating Go code (e.g. linters, code generators). Most of the important ones are already there, and I've transitioned several myself.
As an added bonus, word is that the Go team wants an official package repository system (similar to Cargo, RubyGems etc.). I wouldn't be surprised if this happens rather quickly.