"a system that immerses the stems/roots in water that has a fish tank-type areator pump putting air into the water (like the OxyClone?)" Or deep water culture is more forgiving as in the case of a power cut or a failure in the airpump the plant will last as long as rootrot sets in a failure in a aeroponic system may be fatal within hours in hot weather. A true aeroponic system provides more oxygen and hence will result in faster growth with all other things being equal, don't think I have come across any experiments though, has anyone else? Not all plants do well in a DWC system (plants that hate wet feet) but I am pretty sure all plants will do well in a true aeroponic system. Thanks my take on it anyway.

for someone just exploring the world of hydro, stick with a deep water culture (DWC) system initially. true aero is very dependable (see other threads here) but does involve more upfront cost. a simple DWC system can be set up for something in the range on $30-$40 USD (assuming the sun as a source of light) and will yield good results. grow something like tomatoes, peppers, or herbs to see if you like it and to learn a bit more before expanding on your new found hobby.

I'm with grizzman on this, though you can build a simple system for $20 or less. Once you get the basics of hydro down (maintaining the prper pH and PPM, mixing nuits, starting healthy seedlings), you can try the more complicated systems.

Mike