It looks beautiful. I read much of the text, and I have no doubt that it is every bit as nice in person as it is in the photos, if not even more so. I would dearly love to live in something so nice and with such stunning views.
I think the problem is that it's like building a large, well-crafted house in a lesser neighborhood - it might be worth more than its surroundings, but not too much more, no matter how much it cost to build it. It's only worth what someone will pay for it.
You always want to have a lesser house in a better neighborhood, not a better house in a lesser neighborhood, as far as asking price goes.
That's about $100K more than the owners are asking for the 300 sqm, 4 bedroom, huge kitchen house I'm renting in a closed nieghborhood in Pilar, with 800 sm of property and a decent-sized pool, parilla, 24 hour security, etc. Granted it is not nearly as well designed and executed as the apartment in question.
You would need simply more square footage to get any kind of serious bump in price I think.