1 Hotels are more "sceney/vibey" and tend to attract a younger crowd (20's, 30's). At least that is my experience. I agree with putting them on par with Pendry, Setai, EDITION, etc. I've been to South Beach, Central Park, and I got to see Hanalei Bay before it opened (formerly the Princeville Resort, which they completely renovated and updated). Overall I'm not a huge fan of the brand - I think they are really a 4* that try to look and operate as a 5*, but I have had positive experiences with them.
I would consider Hanalei Bay the only "luxury" hotel in Kauai, but I also thought it's a bit of a monstrosity built into what is otherwise a pristine and dramatic coastline. That's not 1 Hotel's doing, since they just took over the property, but it was a bit of a bummer.