This is one of the nicest places we have ever stayed at, and we've stayed at a lot of really nice five-star places across the world. After arriving by taxi, staff met us on the street and helped take our bags up to the place (even though it's in a perfect location, it's still a few minute walk uphill from the street).
The view from the place is everything you'd expect it to be and more, but that is not the really important part about booking a place in Santorini. A lot of places have views. What most places don't have though is the level of privacy White Ark has. While you're only steps from restaurants and people walking the paths, you're relatively shielded from it all. You can sit on your deck without being too exposed to everyone. We stayed in the large, two bedroom suite, and our private pool is pretty much completely shielded. The infinity pools at the other units are a little more exposed, but they are still super nice.
Our unit had so many nice touches. The dedicated steam room was super nice, and you can even enter pool directly from a window within the unit. Sounds weird but it's really cool!
The beds were perfect and there is no noise whatsoever at night. Breakfast service in the morning is also great and they will bring it to you whenever you specify.
There is nothing I would change about this place. It's really great. Probably better than 99% of places to stay in Santorini. If you want more, you're probably paying many thousands of dollars a night.