MacroMonkey 2.1 released:
1) Now using "LuaJIT-2.0.0-beta6" as the core Lua engine.
2) Added a high low number input argument for unit64 types. Usage example: local Var64 = unit64(HighNum, LowNum)
3) Added windows handle "hwnd" to "win.List()" output table entries.
4) Added a "console.SetColorTable()" to set the console color palette.
5) Updated the "Console Colors.mms" example.
6) The crash log output file name is now "MacroMonkey_Error.log"
7) Added some internal speed optimizations.
8) Now to get the process handle for the current console pass -1 to "process.Open()".

Although LuaJit 2.0 is in beta after testing beta 6 proved to be very stable.
Michael Pall has been working hard on it, continuing his amazing work.
"The whole VM has been rewritten from the ground up and relentlessly optimized for performance. It combines a high-speed interpreter, written in assembler, with a state-of-the-art JIT compiler."
Seems to be quite a bit faster and snapper.
A visual graph http://luajit.org/performance_x86.html (Select "LuaJIT 1.1.6 -O" and "LuaJIT 2.0.0-beta6" 32bit).

Also a big addition is the FFI library allows calling external C functions and using C data structures from pure Lua code.
Introduction: http://luajit.org/ext_ffi.html