Without getting too 'geeked out' in plant terminology, allow us to explain why the AeroGarden works so very well.
Aeroponics is a growing technology that gives plant roots direct access to the air, where they take oxygen out of the air and grow much faster as a result. There are many individual varieties of Aeroponic technology - just as there are many types of hydroponics - and aeroponics is just one type.
The AeroGarden uses a specific Aeroponic technology called Ein Gedi Aeroponics, which grows plant roots outward into air space, and then down into a highly oxygenated nutrient solution. This is an ideal consumer solution because it solves one of the leading problems with traditional Aeroponics, which is that in power outages, plants quickly die. Plants using the Aeroponics in the AeroGarden can survive for days to weeks without power.
When it comes down to 'AeroGarden versus Dirt' - the AeroGarden is proven in independent, university-monitored tests to grow more than twice as fast as the same plants grown in high quality potting soil. For speed of growth and output, dirt really doesn’t come close to the AeroGarden (and is not nearly so cool either).