Out of those 4 pro pins, I'd go in this order:
1. Ghostbusters
2. Game of Thrones
3. Kiss
4. Avengers
I own a GB pro. I love it. Some people will beg to differ...but GB is one of those pins that you really love...or really hate. It's hard as nails...but has that one more game feeling.
I've played a GOT pro. I actually enjoyed it (aside from the artwork) and wouldn't mind adding one to the lineup in the future. I enjoyed the flow on this one and I'd gladly pick a Pro over a Premium.
Enjoyed Kiss too. The only thing that hold me back from ever getting one is that I'd rather own an Aerosmith or Metallica Pro in my limited space as far as a music pin. Especially when priced somewhat evenly.
I didn't care much for Avengers. Wanted to like it but I left playing the game unsatisfied. It doesn't happen often for me. Last time I felt this way about a pin was a Transformers Pro.