By itself Lua is very fast and lightweight. I simple love how you can use it's tables or hash-tables if you will to construct complex data structures. I loved it even to a point of trying to use it to write a simple web application.

Unfortunately Kepler(a Lua webframework) is not only hard to get running but it's docs need a lot of work.

Many games use lua to handle its logic too. I think I may spend some time to learn lua. However, do you guys think that lua will be an universal scripting language like python or not?

It works fine for scripting general things, it's just meant to easily interface with languages like C.