For a Cover Art I prefer Scenes. It is because they are easy to understand and often is a very unified image. They are also closely resembling traditional artworks which is to my liking. The problem I had with this though is that many are overdone confusing mess, or halfhearted in boring, awkward or ugly picture.
I’m not so into Montages. One reason is that montages seem to be very inconsistent from cover to cover or too similar from cover to cover and I don’t like both cases. The first case makes the books seem unrelated, and the other is just plain lazy. Another reason is that they often seem slapdash. They often resemble some children poster project than professional cover art. Of course there are beautiful ones but my experience says that this is rare.
Figures. Another one that is easy to understand that has close tie to traditional artwork. This one has strong impact too becuase we are easily drawn to figures and faces. I think this one is the safest choice for cover art. But then this requires an artist that is really good at figures. I have seen book covers with figures that are unappealing, awkward, weak or stiff. There is also the “uncanny valley” that may 3D figures suffer from.
Symbol/Abstract. I’m really against this. First, this doesn’t reflect the rather fantasy medieval vibe and humour of the book. Second, unless your a wellknown author, such cover often isn’t really eye catching enough. I have seen this kind of covers and they tell almost nothing about the book to me. I had to really puzzle out the title, read the back, and read samples and other tedious stuff. I often judge these kind of covers on title. If the title doesn’t seem interesting… well…