I own three pins. Two of which are ST and TWD. I really like both
games a lot and don't think you'd go wrong with either pin. Lately I've been playing a lot more TWD as I like the shot layout and theme. ST I seem to have much longer games on than TWD so in that aspect it really depends on what type of game you like. The third flipper on ST is a blast as the warp ramp is an awesome shot. I'm really happy that I own both.