Have visited Plakias many times over the past ~20 years, and every year since 2002, yet managed to miss Gio Ma completely until the last couple of years. The food is both excellent and plentiful.
My favourite is the grilled Octopus, closely followed by red mullet, but possibly not everyone's thing!
The place retains a genuine feel, the staff are attentive and, I think, attentive without being intrusive. The spot is wonderful, nicely sheltered from the wind but with wonderful sunset views.
Definitely in our top three and possibly tops!
Richard