I really enjoyed Maria's place. You've got your standard cave room but what you're really paying for is the view (her photos don't do it any justice). Like others have said, there is a decent sized rooftop balcony that gives you unobstructed views of the caldera -- it's absolutely mesmerizing. It should be noted that you do have to go outside to get to the toilet which is attached next door. And there are a decent amount of steps to get to the place but that's Santorini for you. Maria does offer porter service to and from the place which is useful if you have a lot of luggage.