Consider how excruciating it is to try and view source code on SourceForge compared with GitHub. On the latter you are literally shown a listing of files with the README already open for any given repository.

Sourceforge has this absolutely useless "Download" link where you have to grab an archive, extract it, dump it into your text editor, and only then will you find out it's not what you want.

It is not an understatement to suggest that Sourceforge is by people with no idea about open source.