The fast IDO catamaran gets you there in 45 minutes but you miss everything. The slow Şehir Hatları ferry takes around 75-90 minutes but that's the point - watching Istanbul disappear slowly behind you while seagulls follow the boat.

Plus the slow ferry has that classic upper deck where you can feed seagulls and actually enjoy the journey. Fast ferry feels like an airport shuttle. Costs about the same but the experience is completely different.