I guess it depends on your definition of "rare".
It's certainly not Stargazer at under 900 or Quicksilver at around 1200, but certainly less than games like Seawitch at around 2500. I won't chance a guess at typical survival rates for these games. I certainly don't see them popping up all over the place.
I can change it to "uncommon" if that makes you feel better

My attempt at humour is obviously worse than my descriptive ability

Comments are always welcome

I would imagine that it's a big pain TBH. The best approach would be to ship it to the nearest border town and have the shipper hold it at their local depot. Then you cross over, get the game, and clear it through customs yourself. This usually entails telling the US border patrol that you went to Canada and bought a pinball machine. "have a nice day!"
In that sense, American citizens have it a bit easier than Canadians. We generally get hosed with a lot of questions and taxes on any purchases we bring into our country from the US.

If you're within striking distance of the border, this is what I would do... and exactly what I have done in reverse. I have shipped games to Buffalo or Rochester NY and then just popped over to collect them. Paying for brokerage on top of shipping would suck... especailly when you can do the same by just driving it across.

If anyone is interested in this approach, I can recommend a couple of Canadian shippers you can reach out to.

Worst case, you could always sweet talk a Pinside buddy from Buffalo to come up and get it and hold it for you

I think it was just Steve Kirk being Steve Kirk.
The guy had a weird thing with numerology in general and loved prime numbers from what I can tell. That doesn't really explain the 173K but I did once hear someone say that Steve used Nine Ball to push Stern's (then) platform to it's limit and, in effect, show it's weaknesses. People have told me the game seems incomplete as a result, but I can't figure out how.
I find the rules and various scoring opportunities pretty engaging and smart. The game seems complete to me. The fact that he also made certain shoots more attainable via a billiards-inspired bank shot than from a direct hit, is just brilliant. Spinner rubber rebound to 8-ball target and locking balls off the pop bumper are two of my favorite.
The one thing that bugs me is how (if you have two balls locked at end of game) it won't kick all of the balls out. It'll only kick out 1 and leave the other when you start a game. This was a conscious decision by stern to illicit more coin drops via the promise of an easier multiball experience. F2K is similar.

Sure. But what happens to those locked balls at the end of the game? Generally they stay locked to entice another person to drop a coin

Yeah, the game had plenty of issues on route and was unreliable.
The key for a properly functioning/playing Nine Ball is the proper adjustment of the trough and ball lock switches. They can be finnicky, but if they are properly adjusted, the game plays great. In a home environement, keeping these up to par isn't a huge problem.

Damn man! Now I don't want to sell it

There's been a lot of interest, but of course the border is a logistic, financial or even mental block to many would-be buyers.

If it were Spring and I had the ability to bring this down to a show like Pinfest, things would obviously be much simpler.

I'm happy to work with anyone who's genuinely interested and willing to drive up.
We're only an hour north of Niagara Falls... could make for a fun road trip

Funny enough I decided to fold up the machine and bring it to my studio at work. I can enjoy it here for a bit longer and I've made the necessary space at home. If I find a buyer who wants it shipped, I can also more easily wrap and pallet it here.

If not, I'll hold it until Spring and maybe bring it to Pinfest in Allentown.