How such work is received by a human audience is about more than its intrinsic qualities, however. In an objective competition like a game of Go, or when considering a mashup which is simply the synthesis of existing creative works, I suspect humans will be comfortable with acknowledging the achievements of an algorithm.
With original creative works, however, like music, novels, movies, I suspect humans will recoil from even intrinsically appealing creation if it was written by a computer program. Call it some variant of the uncanny valley effect.
We have a romantic attachment to human creation, and it may take a generation of people passing on before we overcome that cultural aversion.