Do you find LuaJIT much faster than a JavaScript engine like V8? That used to be true, but I was under the impression that V8 had basically caught up (unless you need to make a lot of FFI calls, since LuaJIT is heavily optimized for that).
While LuaJIT can't be JITed either on iOS, I think the general consensus is that non-jit Lua is faster than non-jit JS.
I do a lot of bridging Lua to native, and that's another area where Lua is often considered more efficient.
Again, these thoughts may be out of date.