The RDA is similar to the tank in the delivery of the vape. The difference is the existence of the tank to reserve the e-liquid. The RDA lets you build coils to lower resistance to allow more current to pass from the batteries to the atomizer. You end up with a vaping experience at high wattage. The arrangement leads to massive clouds from the burned juice, and this can create a rewarding feeling for some people. The RDA also allows you to switch juices as soon as the wick is dry.