Yes I must admit that LUA is quite good. I to started using LUA for the first time in Minecraft's ComputerCraft mod.
And by using ComputerCraft mod along with RaillCraft mod I managed to make full automated raill system (automated departures based on predefined timetable, computer controllable raill crossings, each station had its own display with arrival times for incoming trains, etc.) but then the server got griefed and I lost everything.
I wish ComputerCraft would alow Importing and Exporing LUA files in Multiplayer games.

But if I ever decide to use a scripting language I would probably go and use DWScript instead. Why?
Since DWScript bases on Delphi like language it means that I can quickly move part of the code from Script to native code or vice-versa by simply copying it. You can't do this with LUA. You would have to do translation from LUA to Pascal and vice-versa.
Also based on many tests which you can find on internet DWScript has verry good performance in comparison to native Delphi code.