Motor yacht vs sailing yacht charter cost comes down to fuel and build cost. A 40m motor yacht burns fuel fast at speed, so its APA typically runs 30-40% of the base fee. A sailing yacht of similar length cruises under sail and lands closer to 20-25%.
Base rates skew the same way. Motor yachts cost more to build per meter, so a 35m motor yacht often prices above a 35m sailing yacht, sometimes by a third or more. Sailing yachts also tend to carry smaller crews, which trims the base fee.
The fuel gap shows up in the itinerary. Motor yachts cover ground: St. Tropez for lunch, Corsica by dinner. Sailing yachts pick an anchorage and stay. Neither is wrong. They are different holidays wearing similar price tags.
The tradeoff is time and space. A motor yacht crosses from Ibiza to Mallorca in hours; a sailing yacht takes the slow, quiet route. If your itinerary is ambitious, the motor yacht's fuel bill buys you the extra islands.
Sources: Windward Yachts
Sail if you want the journey cheap and quiet. Motor if you want the map.