TL;DR...
I have played Houdini, on several different machines setup by different ops , owners, and by the manufacturer (at Expo), and I played OF at Expo.

My take on Houdini... TNA taken to the 3rd dimension, but way less fun. Animations do look like their graphic artist phoned it in from the turn of the century. Callouts that sound only slighty better than "Come here Watson, I need you" or "Marry had a little lamb..."

Oktoberfest is a snoozefest, artwork not that great, the monkeygate issues, twisted sister barmaid... and the Creapy Lederhosen-clad Grandpa Zippy the Pinhead... a Rollercoaster return ramp that takes a minute for the ball to wheedle down... A beer barrel lock that currently is seriously under utilized. The Stein selection and how it helps conquer objectives is a bright spot, but arguably JJPOTC does it better.
Only one thing left to say on Oktoberfest, hope you like death metal polka music.

I can tell you, I am not a JJP fanboy, I have been a pretty harsh critic of Hobbit and DI, and POTC had to grow on me, WoZ was a good first effort, but their “followup” ability to produce the same consistent quality and value both in gameplay and theme on post Oz titles has been lacking IMO, with only the recent POTC being the only exception to that rule.

American Pinball has shanked and sliced it’s fair share of bad strokes and lost the confidence of some players, buyers, ops, and collectors. Houdini may have been a feat to pull off in 4 months, but I think that the abbreviated development cycle shortcomings show through on the final delivered product. Gold Star for effort, but a C+ at best on execution. The title may resonate differently to you, but for me, this is how I see it.

Here is my last observation on wether Houdini is a machine your general pinball player likes, wants, or would fight to own or win...

TL;DR

At Expo this year, at the API booth, they had a bank of Houdini’s where you could play and if you were tops in their little tournament, the prize was a new Houdini machine. Now, there was a wall of like 6 or 8 Houdini machines, and you could play Houdini free and try and win a free Houdini. For almost the entire time the vendor hall was open, they could have set a single Houdini machine out at their booth, put a sign on it that said “play and win me” and they would have had more action on that one machine than they had all weekend on the bank of machines they had set up to run this mini tournament. I really felt sorry for API, because every time we walked past their booth, they would have possibly only 1 person playing a Houdini, the rest of them sat empty and unplayed, yet all the machines at Stern, CGC, JJP or anyone showing off a new pin like TBAG, Kingpin, Mafia, Spooky etc... their machines almost always had a line waiting to play them.

Now some would say, well Houdini had been out for a while, and people had already seen it and played it and so the interest would naturally fall on their new title they showed off, Monkeyfest... which did have lines waiting to play it. To this I respond... Exactly, and you can see what kind of interest people had in playing, competing, and winning a free Houdini machine there was, and lets just say, there were a LOT of pinheads at Expo who DIDN’T wany to play and try and win one.
The interest in winning (or owning) one was just not there, as far as I saw, and most of my fellow players I was running around with agreed, something about it just does not make you want to play it. Ymmv.

Here is a video Ffej Knar (Jeffery Rank) made of Oktoberfest... at the end of the video you can see the Houdini machines setting around unplayed... I rest my case.