...is, in my opinion, not the ugly one or the tasteless one, but the one that gives away the solution to the mystery. I just finished such a book. I wonder how many other readers recognised the spoiler and were pissed off by it? I certainly hope the author was. I caught on as soon as one of the suspects was mentioned, which somewhat dampened my entusiasm for the story, although it was of course interesting to see just how the detective solved the case and got the necessary proof to put the killer away.
The cover design itself is quite stylish and appropriately sinister, although there are some details in the foreground that distract slightly from the overall effect, and the balance is slightly off as well. There will be no cover image this time, and I will not post the title or author in here, because I don't want to spoil it for readers who might otherwise not have recognised the cover image for a spoiler.
(If you really want to know, read the comment, but only if you have to know)