Over at howl.io we've been working on another Lua/moonscript based editor. Incidentally it used scintilla as well until we switched to an in-house engine called aullar. The author wrote a blog post about it: https://howl.io/blog/2016/05/26/introducing-aullar.html
Yes it's great. Interfacing with new libraries is easy with LuaJIT's FFI and implementing low level stuff works well too (e.g. something like reverse find on a string basically gets JITted to C speed).