Headed to Greece soon. Staying at the following:

Grand Bretange in Athens
Salt Suites in Milos
Grace Santorini
Lindos Blu in Rhodes
Kokkini Porta Rossa in Rhodes Town

I'll post my thoughts of each when I'm back home. I'm not really as particular/picky as some of the reviews that I've been reading here, so I'm not sure how much use you'll find my thoughts. Honestly, I'm pretty easy to please, and I'm sure I'll have a great time at each place. I'm mainly just looking forward to experiencing the Greek culture with my wife and seeing the incredible landscapes and views of the Aegean.

Regarding Santorini, I searched the forums on Grace Santorini vs Katikies as that seems to be the two best hotels on the island... I saw a lot of posts here suggesting that Katikies was better. They were 10 years ago so perhaps things have changed. I went with Grace because the views just looked more stunning in the pictures. Also the food looked a little better at Grace and they include something like a 5-course breakfast (I'm a huge fan of great breakfasts). I'll walk over to Oia and have dinner at Katikies just to check it out one night.

My one regret is that I didn't book a few days at Amanzoe... I didn't even know that property existed until after I made all the arrangements. Will probably come back to Greece one day in the future and check it out.