Well, I hate to chime in here but I feel I must.
We purchased a Houdini for our place, #11 actually. It's one of 24 games in the house. For the first 2 weeks earnings were good, as expected with any new game, but then earnings declined rapidly. All other games continued earning as normal.
Issues we've seen so far are as follows:
-Air balls abound, regardless of settings.
-Stuck balls on a regular basis (see cause above). Especially in the Spirit Planchette area
-Upper catapult misses 80% of the time, regardless of settings
-Tight shots, mostly lock shot.
-NO MATCH SETTING (What??!! How was this missed?)
-Insulting players right off the bat. First game, First ball, miss the skill shot and the game insults you!? Now, I like ribbing as much as anyone but even Rudy and The Black Knight at least let you play for a bit before laughing at you or insulting you.
-Poor layout. Milk can shot is, as mentioned before, very risky and unnecessarily difficult. Wide shot on the left orbit, so wide in fact they put 2 switches there so the ball would hit at least one. They should have been adjusted the space on this shot prior to the final build which may have loosened up the tight lock shot.
-Poor Sound. The game has nice, large speakers but even after adjusting the $20 eBay amp they installed which is nearly impossible to get to behind the monitor, the game just doesn't sound good. Very tinny.
-Strange ball mechanism in the Stage. Customer: "Hey, there's a ball stuck in the theater" Me:"No, it's actually a ball welded to lever that's supposed to be there". ??!!
All in all, it seems the fun factor for this game just isn't there. Although some of these issues could be addressed with code, first impressions are over. If performance doesn't increase soon, It'll go up for sale and we'll move on to another title.