Asus I think still runs the same firmware on all their routers. Their QoS is somewhat better than netgear. A subset of the asus routers has the ability to run the merlin firmware which has better QoS. The merlin firmware tends to be more stable than dd-wrt or tomato but only runs on asus routers.
QoS is very tricky to use to solve the issue you have. You are trying to fix the problem after the data has already arrived at your house and eaten the bandwidth. In reallity what you are doing is attempting to trick the end machine watching video to think there is less bandwidth and drop to a lower resolution. If the person using the machine force it to not drop and just tolerates the poor quality the QoS will not solve your problem...