Tholos resort offers great views with the majestic Skaros rock right in front of the hotel. The staff are very friendly and helpful. Every room has a balcony facing the Caldera and in our opinion this is the best spot to gaze upon it and the sunset (far better than Oia!). Some hotels in Imerovigli are situated so that the narrow streets run in the middle of them and right in front of guests' balconies but this is not the case with Tholos. The hotel is very peaceful and quiet and still centrally located. Also the hotel's pool area was very peaceful although we were told that the hotel was fully booked.
We ordered from the hotel kitchen a couple of times. The food was tasty but we found it a bit too salty. Breakfast was served on our private balcony every morning. It was very nice and more than we could ever eat. We had some great cocktails at the poolside bar, too.
Some of the furnishings both in the room and at the pool could be redone because they're not exactly new anymore but the room itself was pleasant enough. Not necesserily "luxurious" but very tidy. Air conditioning, toilet, shower, fridge... everything worked without problems.
By the way, if you are going to Imerovigli don't start complaining about steep steps at the hotel. The town is built on a hilltop and to reach places you WILL have to travel vertically. Also, know that access to some hotel rooms is via the balcony of another. This is normal in, I believe, every hotel in central Imerovigli.