I own both.... They both have very cool art.... MH is a Dave Christensen BG.... hard to go wrong there, but Genie has cool Wizard... it's cool how big he is on the PF.
But playing wise.... no contest, Genie has so much more going for it. 5 Flippers.... upper drops, side stand up targets, lower pop bumper, a spinner..... A lot more to do/shoot for than MH. To me, MH is the most basic Bally of that Era... dual 4 row drop targets & a single saucer...That's it... No spinner, no stand up targets, no double saucers etc. To me, it's a fairly boring game, & I wouldn't own one if it wasn't such cool art. I rarely play mine.... I just have too many other fun early Bally SS's.
Not saying Genie is my most favorite playing game either, but of the 2 of them, hands down I'd rather play it. I have a Widebody from all 4 major manufacturers who made Early Widebodies, Bally Paragon, Gottlieb Genie, Williams Scorpion, & Stern Big Game.... Genie is at bottom of the Widebody list of my 4 for fun. Need to get an Atari Widebody sometime in future I guess to add to the collection.