Book Covers - 2nd Editions

I have noticed, when I have my books in tow for sale, two of my books typically catch the eye of potential purchasers more than others. They tend to select these two books more often after only viewing the cover.

Here are my 4 book covers, which ones appeal to you the most? 

Which ones would you choose at first glance?

What I found, was the chosen two, tended to be The Answer Box and Hanna's New Skill. These two have very simple drawings of the main characters.  This got me thinking, perhaps the other two covers should have similar qualities.

Maybe, the following would be a better cover for The Colorless Forest? 

What do you think? 

Do you like the original Cover on the Left or something new, on the right?

Or, how about the following idea for, Allyssa's Magical Spyglass?  

Which is better, the busier original version or the simpler version? 

I believe, there may be a 2nd edition in the works for at least one of the above books.