From my experience Naxos is less touristy. The wind is stronger. In Naxos, you will have more time and space to do jumps, tricks and loops.
People that I have found in Naxos around September are awesome.

Hey, Last year I spent the entire July in Naxos in Mikri Vigla. Kite Boarding was so much fun as there was continuous wind and sandy beaches. You will meet many kite surfers. Most of the people come there for years so it not very touristy. There are only two schools. Rooms are generally cheap compar...