To your response as a piano teacher for 37 years! I use all methods! It depends on the individual student!
I use the following methods! Alfred Basics, Alfred All In One, Alfred's Chord Approach, Alfred Adult Books, Bastien, Leila Fletcher, Faber & Faber, Piano Town, John Thompson, Glover, Schaum, etc.
When teaching gospel music, I score my own and teach in a process of Theory! Theory is very important in teaching! I also do the National Guild, SCMEA, NTMA, National Federation, and other piano festivals throughtout the State of South Carolina! I presently have two High School Seniors Who are studying Music at two different Colleges. The Male Student attends Berklee in Boston, MA, and the female attends Converse College in South Carolina!