Almost none of the FreeRouter forks are "alive", in the sense that there are being actively maintained. There are a few issues with FreeRouter but none that really bother me. I made a few tweaks to the code. Generally it works well enough.
The question really is "which fork has been most recently updated to be compatible with my system". Some of the recent forks have made a lot of changes in ways I don't like, so I don't use them.