I played both of these games on location for the first time this week. My perspective below may not really help with someone looking to buy the game for home use. It is the perspective of someone that operates games, so take it or leave it as you want. I knew DI was well regarded but I was kind of out of the loop on Houdini as I hadn't paid a lot of attention to it.
I played several games of Houdini with my wife and my daughter. We really enjoyed it. I thought it was easy to understand the objectives and that they were fun. I didn't think anything about tight shots or it being difficult until after we were home and I looked at the reviews. I then remembered that this was a complaint about the game. Maybe it is my style of play, or how the game was set up, but tight shots wasn't on my radar after playing it. I thought it was very well done and came away impressed and wanting to play it more. We had several games that I'd consider rather long. As an operator I left thinking I'd consider getting one. The lower price is also appealing.
I played DI four times. I made myself play it four times because I'd heard so much about it and felt I had to give it a chance. I left unimpressed and not caring if I played it again. It just did not gel with me and I couldn't get into it. I found the artwork and toys unappealing, the theme is obscure, overall it just didn't garner any interest. My impression on walking up cold to each game is that Houdini grabbed me and I wanted to play more. DI didn't have that appeal. Neither my wife or daughter looked at DI or played it. Another thing that I found interesting is I know how many times I played DI because as I mentioned, I made myself play it. I have no idea how many times I played Houdini because we kept putting more quarters in it and playing it again and again.
I know I need to spend more time with DI. I'm not dogging the game, I'm just giving my quick first impression. An impression like this doesn't mean DI is bad or that I'll never like it. It is just what I thought after seeing and playing both games for the first time. I've operated Twilight Zone and that is an example of a game that the general public doesn't understand but players love. Hopefully I'll get a chance to play DI more and figure it out and learn what people find so appealing about the game. But that's the thing, with DI I felt I'd have to learn to love it. That wasn't the case with Houdini. Of course with more time on Houdini I might learn to hate it, that's always a possibility. But as an operator I left thinking Houdini was more fun and would earn me more money from the general public.