Both responses above are excellent, and I can't think of any other important issues other than balanced vs RCA.
Far more components use RCA than balanced, and many that DO offer balanced are not true balanced operation, but only op-amp powered at the output. (So stick with RCA in and out, unless you really have the extra cash to get true balanced units))
Far more components use RCA than balanced, and many that DO offer balanced are not true balanced operation, but only op-amp powered at the output. (So stick with RCA in and out, unless you really have the extra cash to get true balanced units))

