The trip was amazing ! We found that the itinerary was perfect for 8 days, and we decided to put the blue lagoon on the 7th day, to relax after a week of driving. Do decide each day what you want to see the most, because trying to see everything would be too tiring, and maybe not so interesting.
Hotels were nice, landscapes amazing, even with a bad weather (it rained almost all the week...).
We had just a little fright when we arrived at the car rental on the first day, because they did not have our rental (there was a misunderstanding between them) but we called the customer service and sent a mail, and 10min later, we had our car, and we got upgraded.