balanced connections require* transformers, which can (or necessarily do, depending on who you ask) color the sound.
some crazy people, like me, find that desirable 🙂
the benefit of a transformerless, unbalanced connection is a cleaner signal path, but it's more prone to interference. with short, careful runs it shouldn't be an issue (e.g. don't run an unbalanced line parallel to a power cord).
* i'm _pretty_ sure they're required, someone please correct me if i'm wrong