I reckon both interfaces could do with a tad larger margin, possibly showing the controls on hover? the fixed row height one should center the book and have a

I reckon both interfaces could do with a tad larger margin, possibly showing the controls on hover? the fixed row height one should center the book and have a neutral background, I do think the alternate one looks cleaner, however if you expect people to do something like rate / save a row of books then the positioning being inconsistent will be annoying, if you only expect them to click through single books then the seamless one gets my vote