Why go back? Because, if the circumstances allow it, it offers a known good landing surface, aircraft savvy people, and possibly some emergency services; not to mention a lack of power lines and other such obstructions. Personally I wouldn't be worrying about the runway, any bit of clear space would do.
However, for whatever my opinion is worth, as I said earlier I don't really advocate turning back. The 'Golden Rule' is golden for a reason - that's not to say there aren't exceptions, but in flying I'm a big proponent of the KISS principle.