I have been sending clients to Santorini for many years. The feedback is always amazing and it is clear to see why. This is a must see destination in my opinion.
Oia is the main hill top town that everyone has heard of on the very northern tip of the island and is a photo opportunity around every corner. Thankfully it is as beautiful in real life as the photos present it. This is where several top hotels are situated. We stayed at Katikies and visited Mystique, Perivolas and The Grace, which is slightly further from Oia in an area called Imerovigli. They are all wonderful and have their place. I am happy to discuss the differences and help choose the right one for our clients.
Katikies is the original style trendsetter and is right on the tip of the town so easy access (after you climb the steps). Perivolas has a gentler charm and feels like Santorini must have felt before the current trendy set arrived when it was genuinely cool. The Grace is in a different setting looking back to Oia and has an incredible infinity pool. It is about a 20-minute drive from Oia. Mystique has the most outdoor space and a lovely main restaurant area by the pool with an easy 3-minute stroll to Oia.
The rest of Santorini is covered in vineyards and smaller villages on the flatter side of the island. I describe it as a wave with the breaking edge as the cliff top and the rest is a gentle slope with a calmer life to be found. A lovely combination would be a few nights on the cliff edge and then some time at Vedema resort on the flatter side to really see both sides of the island.
People will often say to avoid Santorini if you have difficulty managing steps but the solution would be to stay on the flatter part of the island at Vedema and then take a car up to Oia for the afternoon and evening. You then have a relatively flat walk through the high street and all the views from there.
Everyone talks of Venice, Rome, Athens, New York etc. as their must visit places and I would now add Oia in Santorini as high on that list.