I believe I have some relevant info about github. I have a repository at github. http://www.github.com/danmar/cppcheck I used sourceforge+svn when I started cppcheck. But then I moved the code repository to github.
For the code hosting I think github is really good. The code review features are really useful. It is simple to make forks. The biggest disadvantages with github is that its bug tracker is not good enough and there is no release management.
- How many people contribute to one, and what hosting service do they
use and what is the experience, is performance consistent and better than Sourceforge SVN, all around the world?
30 people have contributed to cppcheck according to ohloh. Most of those contributors only provide a few patches and nothing more.
I would say that github has consistently better performance than sourceforge. Not just the repository but also the webpages. It has happened that github has been down but in my feeling it has just been temporary technical problems.
Best regards, Daniel