Owned both, if I were to buy one back it would be zombie. Like some of the music, but not a fan by any means.
Houdini is a more serious game. Tight shots that make you focus. Its got a great looking of, but the sound package is just OK and the display graphics are nothing to write home about.
Rob zombie, is irreverent. If set to adult video and sound its unique. The speakers will shake the house and always found it to getting me to play one more game.
Between the two houdini was better assembled at the factory. Both Rob zombies (started with a regular and the got an le) needed work. Both needed small things adjusted, one needed the ramp to the rear vuk moved. Both needed the coil lugs solder touched up because whoever did it st the factory didn't use enough. After that, both were rock solid and required nothing.
Id say both are flawed games in their own way. Rz didn't get all the code features spooky promised. Houdini is love or hate do to the tight shots. Big question is wh a t kind of game do you want in your collection?