In the main, the two parts of doing anything new are: "what & how to do it"; and then "do it". Web lessons seem far superior to me with respect to "What & how to do it". To name a few, my reasons are:
1. gives the student the ability to replay the lesson over and over again
2. gives the student unlimited flexibility to schedule their lessons to fit any schedule
3. high quality instructors at a much lower cost

With respect to the "do it" portion of learning, it will greatly depend on the student's ability to stay focused and their use of self-discipline to succeed with web lessons. Some students need the live interaction with another person to help keep them focused & stay on track. Web lessons allow the student to skip through difficult drills and move on before they are ready, perhaps. A live instructor will not allow the student to do that.

What's the best? It just depends on the individual student IMHO.