I would not consider myself a pinball expert or wizard by any means - just have fun playing them. I currently own all three. GNR is an amazing light and overall sensory show with the music videos and such, but the gameplay is kind of wonky and my least favorite out of the total 6 games that I own. Lots of multiballs and you never really feel like you can get going with it.

AC/DC and Metallica are both awesome games - I LOVE both bands and the music. AC/DC is cooler to look and interact with but Metallica has an awesome flow to it. I would say AC/DC is the more challenging of the two games as I seem to drain SDTM quite a bit. You cannot go wrong with either.

One side note is that you could probably pick up a GNR LE for a good deal at this point and play for a little bit while you look for the Metallica or AC/DC that you really want. I have the Metallica from the original 2013 release and then AC/DC Luci from the 2018 Vault and my personal POV is that I would look for a vault edition of either.