This was our first Oceania cruise, having used Celebrity and Cunard in the past. We booked on the basis of the itinerary (Greek Islands) and the reputation Oceania has of being a solid notch above the mass market cruises. The cruise originated and ended in Istanbul.
Embarkation was easy with a maximum of 15 minutes to drop off the luggage and check-in.
Tip - if you are looking for well known Western brand hotels close to the cruise terminal, I would recommend the Grand Hyatt or Intercontinental, both close to Taksim Square and less than 10 minutes by taxi to the ship.