Easy way to answer the question:
1) Which band puts you in a better mood when listening to their music while driving... AC/DC or Metallica? I choose MET Premium over ACDC Premium because AC/DC songs bore me and I skip over them. Metallica is awesome. People who like AC/DC music and not Metallica will likely prefer a machine based on that alone.
2) What excites you most, listening to Metallica and/or ACDC or listening to zombies being slashed? If you prefer a zombie theme over a music pin then go for TWD. The topic is really about which music pin is preferred, but if you like zombies over music the answer is simple to me.