GitHub offers Free Trial, but Phase does not.
GitHub is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Phase is designed for and undefined.
Pricing for GitHub Starts at $4/User/Month whereas for Phase Starts at $12.00per user / month when Billed Yearly.
Some top alternatives to GitHub includes LiveCode, Codeanywhere, Visual Studio IDE, CodeinCloud, GitLive, Microsoft Azure, GitLab, CodeSee and Bitbucket.
Some top alternatives to Phase includes and undefined.