Long ago (in a company far away!) I evaluated Lua vs Python for use in a simulation engine as a scripting language for extending behaviors of stuff. Lua won, because of the easy integration with C and it's general lightness. However, I prefer Python. The big reason I like Python is that it doesn't try too much to be elegant, and happily creates specific functions for specific usages. I was able to get more done, more quickly in Python, even though I, from an aesthetic standpoint, though Lua was ... neater.

I've since used Lua on numerous occasions, and I still love it. But I always reach to Python because of it's pure, raw usability.