Both options have a clear use case. Self-drive rentals suit short in-city trips, business travellers who prefer independence, and confident drivers who know Islamabad's roads.
Chauffeur-driven rentals suit airport transfers, weddings, corporate travel, and any trip outside the city such as Murree or Naran, where a local driver's route knowledge matters more than the extra cost. Chauffeur rentals also remove the need for a security deposit tied to the vehicle.
As a rule of thumb, if the trip involves mountain roads, night driving, or you simply want to relax in the back seat, book with a driver. For quick errands around Islamabad and Rawalpindi, self-drive is usually the more economical choice.