But if you have newer and better media and want to keep the existing ones (remember, it doesn’t replace — it deletes all media before downloading), then it would be more effective to compare:
Is there media available to download?
If so, is it more recent than the one saved on the PC? If yes, replace it; if not, keep the existing one.
Compare the metadata. Is it more recent than the one saved on the PC? If yes, replace it; if not, keep the existing one.