I have been teaching one to one for four years now. One thing I have learnt in that time is that there is more than one way to crack a nut!
The great advantage of one to one is that it is student focused. For example, I have had one student who had little formal education in her native country. We spent a lot of time fine tuning conversation, learning to recognise letters and words. It was a meticulous approach, and deeply satisfying for both student and teacher when it started to yield some progress.
On the other hand, I have worked with advanced students with an academic approach to learning. Advanced students are equally rewarding because ultimately it is about ridding them of their native mannerisms. The student begins to enjoy pronouncing words in an English style or using just the right phrasal verb.
For me, there is a pleasure to be had in finding just the right way to crack a particular problem.