Personally, I hate mid series cover changes. I'll admit, sometimes the new covers are better than the original, but for someone who owns the released books in the original covers, it's enough to make me want to stop buying physical copies of that series.
There are exceptions, of course. Most notably the changes made to the Blood of Eden series by Julie Kagawa, but they also had the decency to change those covers after the first book, not the second or third. And they solved a bit of a snafu by changing the cover of The Immortal Rules from a Caucasian looking model when the main character is of, at least partly, Asian decent. Personally, I liked the original cover and the new covers equally, but appreciate that the publisher heard the public's concern and stepped up. My problem, is that sometimes there's no real reason for the cover changes. Sometimes publishers just change things up because. Because they decide two books into the series that they aren't selling enough to a certain demographic? Because the readers they've hooked will follow along with the changes anyway and now they can snag twice as many? Because what, exactly? What makes them decide to change things halfway through? I know there are probably a million reasons for a cover change, ones that probably make a lot of sense to the publisher, but for me, the reader, I hate it.
When it comes to eBooks, I don't care about cover changes. The cover usually automatically updates and I don't even notice most times. With an eBook, it's content is all that matters to me, but physical copies? I usually buy them for the cover, or because I love that series so much I need to hold a physical copy in my hands. So when the publisher up and changes the cover on me mid series I feel betrayed in a way. I have a thing about having matching series, and when a publisher changes covers or stops printing hardcovers or whatever, it makes me very sad. Like I said, I understand there are a number of factors to take into account when changing the covers of a book series, but whenever I get wind of a change all I feel is, "Why would you do this to me!"
The most recent cover change that made me want to rip my hair out is The Arcana Chronicles by Kresley Cole. Poison Princess and Endless Knight were two of my absolute favorite books two years in a row, and the covers are absolutely gorgeous. So when I stumbled upon a new look for one of my favorite series I immediately thought "Ew. They look like lame, generic adult urban fantasy novels now." Is that a harsh thing to think? Maybe. But do they look like the covers of an intriguing YA apocalyptic/dystopian now? No. I don't like the new covers and it makes me sad that they've taken such a vibrant series and made the covers so bland and boring. I'm not sure if they will have two covers (hardcover and paperback) for Dead of Winter, but I'm going to venture a guess and say no, they won't. Unfortunately.
How do you feel about mid series cover changes? Do they drive you nuts, or do you enjoy the change up?