I ranked the quality of Zarahemla and Parables bookcovers over time. Time runs left to right, quality of covers top to bottom. Note that I have not taken disparity of quality into account. If I had, there would be some big gaps between the better covers and the worse. But I've been accused of snobbery too many times to risk anything other than putting them in order from best to worst. I'll let you decide for yourself how many are good and how many are terrible.
Of course, this is just my opinion. If you click on the charts, you'll be taken to the pubs' catalogue pages where you can see them larger. Do so, then return and tell me which ones you like most and least.