I've run into this problem myself. I've tried a few times to contribute to GNU software but for whatever reason my code just never made it in. Definitely sucks to spend time learning a project and sending patches only to end up with nothing.

Still preferable to being completely at someone else's mercy though. It is always better to have the option to maintain a fork if needed. I actually maintained my own custom fork of bash for quite some time. About a year later upstream added the feature I wanted so the fork was no longer necessary. It was a pretty good exercise though. Maintaining the fork turned out to not be that hard. All I had to do was pull upstream, rebase my branch on top of upstream, recompile and repackage. It is always better to have the power to do this than to not have it.