What people often don't get about MB basically comes down to two things:
1. The factory settings are WAY (I mean WAY!!!!) to easy. Change the settings (no body part spotting, no DRAC letters on game start, timers down, etc etc) and set the outlanes to be wide open and it will not be an easy pin at all any more.
2. The ruleset is very simple, but it's catchy as hell, a true Lyman masterpiece. The fact that almost everything is timed and you can stop the timers by starting multiballs makes for a very fun strategy twist. You are basically trying to avoid starting any multiballs (which is not so easy as it seems) until you have all the modes set up and then start them all at once.
The timers (and the theme and the music) are the main factor that make me prefer it over MM (which is also a great game). I'm aware that few people will share my opinion but for me MM feels much more repetitive than MB as there are not really timed "modes" in MM but multi balls instead. Not much pressure is put on the player to accomplish things in time but rather to keep multiple balls in play. It's just crazy fun again and again trying to stack as much modes as possible into Mosh Pit or Frank Multiball on MB. And while Monster Bash is easy to reach, the final wizard mode Monsters of Rock is hard to get with the right settings.
RBION is a great game to which i plan on getting soon, but MB will always be my favorite, the complete package it offers is just awesome fun. It was my very first pin and still, whenever the shine of "the current new one" in the gameroom wears off MB is always the one that gets the most plays.