When I was planning my trip, I thought about cutting out Santorini completely. I'm happy that I kept it in my itinerary, but that being said, it's the one island I visited that I wouldn't rush back to. It was the first stop on my trip, so I was instantly blown away by its sheer beauty. But it's one of those destinations that is almost ruined by over-tourism. Everything was very overpriced, wildly busy, and "Instagrammable," which sadly made the island lose a little bit of its magic for me.
I did some things I would highly recommend: Sunset in Santorini was extremely chaotic, so I woke up to see the sunrise at the edge of Oia in peace and quiet. I found some restaurants away from all the crowds (Armeni and Metaxi Mas were two of my favorites), I walked a stretch from Fira to Oia, which really was breathtaking, and I took a boat tour to see Santorini from a totally different perspective.
I would encourage you to go to Santorini for a brief visit and see it for yourself. Spend a day...maybe two, take in the beauty, and then make your way to the other islands.