What can and can't be copied
Due to technical limitations with iTunes, not every type of item in an iTunes library can be copied to another library (this applies to both copying music and video and merging libraries). Below is a summary of what can and can’t be copied, with workarounds described where possible.
Music, movies, TV shows, audiobooks, iTunes U, and ringtones: all these music and video tracks can be copied from one library to another.
Playlists, playlist folders, and smart playlists: all your custom playlist organization can be copied from one library to another.
Track metadata: most track metadata can be copied along with the media files. The main exception is the “Date Added” field, which iTunes automatically sets to the date and time the track is imported into the library. iTunes does not expose a way to change this value after the fact, so if you copy tracks to another library, the tracks in the destination library will have the date that the copy was performed, not the date that the track had in the original library.
Artwork: album artwork can be copied along with your tracks, though the details of this can differ depending on whether the artwork was downloaded from the iTunes store. You can read more details about how this works in Copying Album Artwork.
Podcast subscriptions: iTunes does not make available the links to podcasts that you’re subscribed to in your library, so there is no way for PowerTunes to copy those subscriptions across to another library. Copying your subscription list manually is not too hard though, and that is described in the Copying Podcasts page of this manual.
iOS apps: iTunes does not publish the list of apps you have in your library that can be synced with your iPhone or iPad, so PowerTunes is not able to list these or copy them to another library. This can also be done manually, as described in Managing iPhone Applications.
iTunes Extras, iTunes LPs, PDFs, and iBooks: iTunes does not publish information on these items in your library, so there is no way for PowerTunes to list these items or copy them to another library. Note that as of OS X 10.9, iBooks are now handled by a separate iBooks app on your Mac, instead of via iTunes.
iCloud tracks: If you use iTunes in the Cloud or iTunes Match, iTunes only publishes information about those tracks that have already been downloaded to your machine. If you have any tracks that are in your library, but haven’t been downloaded (i.e. the “iCloud Download” icon appears for the track in iTunes), those tracks will not appear in PowerTunes, and cannot be copied to another library.