ive used both before - for me, avent works better for me, i achieve lets downs and manage to get more milks than the medela swing.
i think it depends on your body, for me, even with the dual pumps, Avent versus Medela versus Ameda, i get the least from the last and most from avent, in sequence.
thanks mummies for the reply..i myself loved the avent electric pump. Tried brands like medela and pigeon but found avent to be the best. More milk, less pain.