I go to GitHub to find a project first because that's where I hope it is. GitHub's UI and culture go a long way towards standardizing repo layout in such a way that I can more easily use it, plus if I find bugs or issues there's the Issues and Fork links right there.
In my admittedly anecdotal experience, GitHub projects are way more likely to have a clear overview with a link to a GitHub Pages site with real docs, they're more likely to define the rules/procedures for sending in contributions, and they're more likely to have an active community of contributors. I know I'm not going to have to hunt for the source link in a paragraph somewhere, because if I know the repo name and author I can clone the source.
In my admittedly anecdotal experience, GitHub projects are way more likely to have a clear overview with a link to a GitHub Pages site with real docs, they're more likely to define the rules/procedures for sending in contributions, and they're more likely to have an active community of contributors. I know I'm not going to have to hunt for the source link in a paragraph somewhere, because if I know the repo name and author I can clone the source.