Help - dive shop recommendations please for Santorini, Greece?

Hi all,

I am going to do my advanced open water on Santorini, Greece in June - does anyone have any recommendations please of a good dive operator to go with? I'll probably end up doing 6-9 dives, so i'm looking for some variety in the dive sites we go to.
Did anyone find the diving there disappointing in terms of diversity of marine life, or is it an interesting place to dive?

Thank you!

The only PADI 5 star IDC centre on Santorini: [http://www.navyswaterworld.gr/en]