> It's unsupported software. If it works, great. If not, you're screwed.

Not entirely sure how you got to that conclusion. Afaik there are no know bugs. All issues on https://github.com/LuaJIT/LuaJIT/issues are related to adding further optimizations or otherwise improve LuaJIT. In the last year bugs have been fixed almost instantly after they have been posted to the LuaJIT mailing list. So while I'm still a bit sad that Mike is on his way out, I wouldn't call LuaJIT unsupported. It's still a great choice.