Much of the Greek charter fleet is based in the area mostly at Alimos marina (Kalamaki)
Flights to and from Athens are numerous and good value. Getting to the departure marina is easy and quick.
Enormous selection of charter yachts
Two attractive itineraries for a one week cruise
You must cross shipping channel at start and finish (tiresome)
Crowded with other charterers less competent than you!
They are 6 night/7 day itineraries that with thought can be combined into 14 day cruises. If you have that long, consider the Southern Itinerary and continue south down the quieter East Coast of the Peloponnese.
Poor holding for your anchor makes this an unreliable place to berth. There are plenty of good anchorages and the occasional pier along the west coast of the main island that make better places to stay.
Fourni is wonderfully wild with few tourists; those that do come are made to feel most welcome. Join them, do.