The most important single thing about string theory is that it's a highly mathematical theory, and the mathematics holds together in a very tight and consistent way. It contains in its basic structure both quantum mechanics and the theory of gravity. That's big news.
Is the universe 'elegant,' as Brian Greene tells us? Not as far as I can tell, not the usual laws of particle physics, anyway. I think I might find the universal principles of String Theory most elegant - if I only knew what they were.