Guys, Greece is what dreams are made of. It's definitely a place that needs to be on your bucket list. Everyone needs to go there at least once! I went to Santorini for three days, and Mykonos for two. I would recommend staying in Santorini for 2-3 days and head to a different island, because there's only so much to do there. (swim and sightsee) The yacht excursion is the easiest way to see the best spots in Santorini near the water within 4-6 hours. Book the later excursion so you can catch the beautiful sunset at the end of the day!
Mykonos has beautiful beaches. Santorini beaches were a little harder to access and weren't as nice as the ones in Mykonos. Mykonos overall is very nice area, whereas only the inner city of Santorini was nice. The shopping and food options in Mykonos are amazing as well. Mykonos is more flat, whereas in Santorini you climb a million stairs no matter where you go. Mykonos is really big on the night life scene, lots to do in the evening. The streets are crazy in both cities, definitely don't want to rent a big car. 85% of the people there drive scooters and four wheelers because the roads are so small.
Both places are gorgeous and a must see! Xo