Well, it is weird to compare fully interpreted Lua with Compiled JS.
I like my scripting languages to remain as loose as possible, so I avoid compilation.
It makes all tests easier, requires less set-up steps before running them, allows me to change scripts during runtime, are easier to debug depending on the compiler.
I only compile the scripts (using Lua's own compiler) when I want to send the built project somewhere, without source code. But I don't think that brings any considerable performance gain, in this case.
Also, the different syntax is a pro on my account. I often got myself writing C++ code on my script editor when I was using C-like syntax scripting. Different syntax makes it easier to differentiate both, so I don't end up overengineering my scripts nor neglecting my low level code.
I have a personal rule, if my script performance is affecting my game, I'm doing something wrong.
So, between these two, I would not really care that much. They are both easy to learn if you don't have experience.
Performance differences shouldn't really be groundbreaking or anything.
Go with the one you are most comfortable with!
I would personally pick Lua without hesitation.
Edited by dejaime, 23 December 2013 - 08:33 AM.