IMO Ebb and Flow would be the best for someone new. Separate res makes it easy on the grower and the plants. Each one has it's initial investment. DWC is very easy as well, but can be difficult to clean. There is always the issue of res temps with DWC, as the roots are constantly in the water. If the water gets too warm you loose oxygen supply to the roots.
Aeroponics is said to yield the most, and finish the fastest. Great for a production grow but not the best for taste and quality.
Like puffpuff said as well, it must be dialed...as the grower needs to be as well.
Have yet to see a design more efficient than the UC system. A high pressure aero would probably come very close but the price difference between a UC system and high pressure aero would be substantial. Also, the UC system would be easier to maintain and learn on as opposed to HP Aero.
You can grow some serious ass tree's in a very short amount of time with the UC system. The UC system has one thing that the Ebb and Flow does not have, and that is the "negative" flow of the water which creates a unique environment that no other system does by design.
THe Ebb and Flow is a very fine method for growing that is cost effective for sure and please do not interpret this as anything negative about the system. It is hard to say anything negative about the system, but compared to a UC system, the UC will perform better and use less amount of nutrients.
No other system uses less nutrients, which is a huge factor as cost of nutrients is not cheap. Most are able to cut the amount of nutrients used by as much as 65%. That is not just a little less, that is lot less in my book!
Also, plant numbers is always a huge concern to most growers trying to stay compliant and still produce enough meds for patients. The UC system takes the plant number game out of the equation.