Both IMO. Patches + mailing list isn't an ideal medium for code changes, and it's not as easy to quickly browse a list of patches that haven't been merged yet.

Both IMO. Patches + mailing list isn't an ideal medium for code changes, and it's not as easy to quickly browse a list of patches that haven't been merged yet. GitHub lets you update patches easily (and see the updated patch), drop comments inline in a patch (very useful for code review), and tag patches (extremely useful for large projects). Having to go through the extra hassle of a mailing list just to have the maintainer ignore them sucks. Another benefit of GitHub is that users affected by an issue that has been patched but not merged can just fork the repo and merge the PR themselves and use that (I've done that in multiple cases). Mailing lists aren't as easy for this.