In both Amarok and Clementine, you can right-click to edit tags, and can edit basic information such as release year or genre on all the tracks in an album at the same time. But Amarok goes beyond the basics, with lyrics, statistics, and custom tags as possibilities. Because you can permanently add this additional information, Amarok is automatically easier to search or to create automated playlists that satisfy you.
Verdict: Amarok. This is one situation where focusing on being complete is not just a preference, but a valuable feature.
Clementine allows you to create and shuffle playlists, but, when you are building playlists, you are largely on your own. This state of affairs is in marked contrast to Amarok, which can automatically create playlists based on every criteria listed in the tags, from artist and genre to song length or release date.
In the end, if you want a playlist that contains exactly what you want, you have to add tracks manually in Amarok, just as you do in Clementine. All the same, Amarok's automated playlists can generally create a playlist that you feel like listening to, provided you enter the criteria that you're in the mood for.
Clementine does include tabs in the playlist pane, which are easier to switch between than dragging a new playlist from the source pane, which is what you have to do in Amarok. However, the advantage is minimal, especially since most users of either music player are likely to be conditioned to look for playlists in the source pane anyway.
Verdict: Amarok. If the Clementine team has plans for automated playlists, they have yet to be implemented.
Both Amarok and Clementine allow you to collect covers so that you get more of the traditional listening experience. However, Amarok is much more interested in giving listeners as much of the traditional experience as possible.
In addition to the cover manager, Amarok includes the middle context pane, where you can display such information as lyrics, artist photos, upcoming events that feature the artists and listing of similar artists. It even offers Wikipedia entries as a substitute for linear notes.
So far, at least, Clementine shows no signs of providing any similar information. In fact, although I could be wrong, my impression is that many of its users would prefer that it never does and considers such information unnecessary.
Technically, they are right, but the extras can be informative, and can help you to discover new artists or releases. Besides, in Amarok, you can select the ones you want, or even hide the middle page altogether.
Verdict: Amarok. If you care about context, then it is another area where emphasizing completeness matters.
With several releases in the second series of releases, Amarok has built up a large ecosystem of scripts for online music and lyric sources, as well as minor pieces of functionality such as copying tracks.