I find Lua more interesting than Python. It has all the simplicity, all of the power, none of the indentation, and is quite a nice portable tool. That said, I do wonder at times what it is about Lua that makes so many people not-interested in it, when .. from my naive point of view .. its an almost perfect language for rapid development. I don't have that feeling about Python, quite so much ..
Lua the language and LuaJIT the third party vm are great. But there is no general purpose standard library. Like in C one has very limited libraries that are shipped with Lua - that's fine. Though I really miss a good website with a list of additional up-to-date libraries and a community around it.
Lua needs a better project website, like PHP where you can post code examples as comments. At the momemt the Lua website is stuck in 1999. The wiki software is bad, the only way to stay in touch is the mailing list, etc. The LuaForge website is outdated. Finding various libraries is pain. Many libraries are hosted on servers that don't exist anymore or are for Lua 4 or 5.1 but not 5.2.
A lot of users use Lua in closed source software as embedded language (video games, Adobe programs, etc.)
Imagine if all those libraries that you find for Python would be available for Lua, it would be great.