I also played a few rounds recently at Ardfin. I agree - David has done a great job of describing the Ardfin proposition. And when it comes to the course, his video really speaks for itself. Robin is also right - as David acknowledges - that if you see the course amid less clement weather then your impressions will likely be a bit different. Of course you can say this of any course, but i think it applies especially to courses where the canvas is so dramatic.
I played three rounds and the weather (mostly wind) was pretty difficult for two of them. In such circumstances it is unquestionably a very challenging course - in a word, penal. Short par fours like 8 and 9 look alluring on the drone video, but played into a 25mph wind are very, very difficult!
Leaving the weather aside, no question it is a very memorable experience. A strong and challenging course on a dramatic site. I think there are many excellent holes and none you would say are weak. The biggest issue is playability when the weather is tough - there is just not enough margin for error so lots of balls are lost. Over time this will likely be softened, but the terrain will only allow so much. How much you aim off for weather, and hence playability, in your assessment is a matter of opinion.
In terms of rankings, comparisons are odious, but to take a topical course - Winged Foot West - which ranks 23 in GOLF magazine. If cost were no object and you only had one round - i think I would send a golfer to Ardfin if you were looking for a memorable experience. If you were a connoisseur of green complexes and want to marinate in US Open history, maybe you go to Winged Foot. Personally i don't see it in quite the exalted company some others do, but I do think it belongs in the conversation among the best modern courses i have played, and you will have to see a lot of courses to play one more memorable.
On the issue of cost i would make two points. First, when you compare it to the sorts of prices being charged for high end public venues mentioned like Whistling Straits and Pebble Beach, you can make a decent argument for Ardfin and it would be based in part around exclusivity. There is a whole world of difference between the experience at Ardfin, where you are very likely to have the course to yourself, amid a very dramatic natural setting, and some of these other industrial scale operations where you are extremely aware of the commercial purpose of it all. And that difference has a value, for sure.
Second, many of the world's best courses are socially exclusive and will only ever be accessed if you know the right people. Courses like Ardfin are financially exclusive but are, at least theoretically, accessible to all. Whether you want to pay that much for golf is partly a matter of taste. No question it is a LOT of money and it is 100% rational to say there are many other treats you can savour before you get to that tariff bracket, if ever. It is a course you might hope to play when the stars align but but not one you have to put right up top of the list of a GCA education.
All that said, hats off to Greg Coffey and Bob Harrison. The world of golf is richer for their efforts and I hope many more get to see the course.