Should similar story lines matter?

My latest book got me thinking, probably more than I should, but it did. I even had to ask some of my students about it.

I was reading this book that was interesting to me. I read a sample on my Kindle several weeks ago and liked it enough that I bought the book and the sequel. When my books arrived and I continued to read it, I couldn't decide if I liked it or not. It was a good enough story, don't get me wrong, but here was my problem: this story had a lot of similarities to two other questing type stories (that are/were wildly popular) that it kind of bothered me.

Have you ever heard a song on the radio that you liked, then later you found out it was a remake? You listen to the original and decide that the first version you heard was the version you preferred.

I feel like this is where I'm at with this book. It was a good book that drew me in and I finished it in less than a week. I am even 1/3 of the way through the sequel. I just can't decide how it compares to the other books and it is clouding my judgement of the book.

It bothered me so much that I checked the copyright dates of the books to see who had the ideas first to try to ease my mind. One of the similar books was printed starting in 1954 and the final books printed in 1955, the other was in 2001 through 2011, the book I just read was printed in 1991 and the second is 1998.

I still like the author and she wrote one of my favorite books, I just can't decide how I feel about these books. Should this bother me like it does? Should I like these books because they came before the other popular books?

Have you ever had this problem of similar story lines distracting you?