SourceForge is an awful interface for development. The only reason to go to SourceForge for Linux users is if the project is new enough that you need to download the source and compile it yourself. I've seen more and more new projects moving to GitHub or BitBucket instead of SourceForge. SourceForge's user interface, bug tracker, wiki software, is kind of awful. The newest development isn't happening on SourceForge, it's on GitHub.
The projects still on SourceForge started there when SourceForge was where to go. They're all old enough that they're mature and in the package managers.