Wired Science Blog:
ATV missions are expected to launch every 12 to 15 months and will stay docked
to the station (providing 45 cubic meters extra pressurized volume and station
boosting capabilities) for up to six months.
After the mission is complete the ATV will remove up to six tons of garbage from the station and be allowed to burn up in the atmosphere on reentry just like the Russian Progress vehicles.
These ATV's could be very useful in delivering crucial supplies and equipment to the ISS and future space stations. They provide a relatively low cost and risk free method to get cargo to the ISS and may prove to be very reliable. It is also an added bonus that they can add space to the ISS for extended periods of time. The one con in my opinion that adds to their low cost individually is that they aren't reusable and that they simply burn up in the atmosphere, though I guess this takes away the need for a place for them to land and makes it so that they don't require all of the equipment for reentry. Well, hopefully these ATVs will fulfill their purpose and help with ISS development and sustainment. Only time will tell.