A bit late to the party, but here's a short story and my opinion.
I faintly remember playing Sonic's Hang-On pinball machine. It was the early 90's, I was about 10-12 years old. The location was a small arcade in Malgrat de Mar, on the sun-drenched Costa Brava. Pinball was everywhere on the Spanish coastline at that time period, mostly the now famous WPC titles like Funhouse and The Addams Family. And I loved it. I was a kid and just wanted to play them all.
The arcade with the Hang-On was in a more quiet spot in the village. It was quite rundown and clearly not popular enough to be able to buy the newer fancy machines. Their pinball line-up consisted of Hang-On, Star Wars (the 1987 version, also from the Sonic brand) and two older American machines, probably Williams System 11's. One of them might have been Big Guns, I'm not sure.
I remember being intrigued seeing the two machines, as I had never seen them before. I also remember, when playing them, that the Hang-On and Star Wars both felt very unfair compared to the other two machines. Ball speed was crazy and unpredictable, the flipper gap felt too big and ball times were extremely short. I also didn't feel that making the shots made anything spectacular happen. Today I'd say that the software was extremely barebones.
I think I played one game on both Sonics and feeling that was more than enough. I rather put my valuable Pesetas in something that felt like a honest and fun game of pinball. Today, I would play it more, just for its rarity.
If collecting extremely rare titles is your thing, Hang-On might be interesting. Hang-On is a pin that most people, even pinheads, will never see, play or even know about. But: the rarity is the only thing in which it tops Demolition Man. DM is a far, far better game in every other aspect.