The design has proved very popular with Londoners and tourists alike. Its two main advantages are the open platform at the rear, and the presence of a conductor to collect fares, required by the isolated driver's cabin.
The platform allows large volumes of passengers to quickly alight and board at stops, and indeed at traffic lights and slow speeds (Wikipedia does not recommend such foolhardy behaviour!). The conductor collects fares when the bus is travelling, which considerably reduces waiting time at stops.
Many of London's bus routes switched to modern "one-person operation" in the 1980s, out of a desire to reduce operating costs after privatization. However, it has been found that the increased boarding time, while each passenger pays the driver, slows down busy routes, leads to "bunching" of buses and a poor service.
Ken Livingstone, Mayor of London, has guaranteed the use of the Routemaster for years to come. For many people, Routemaster buses evoke nostalgic feelings. See also the television sitcom (later a film), On the Buses, although the buses depicted there, while double deckers, are not Routemasters.