One on one on be very beneficial, you have someone you can ask questions. It may take a while to find the instructor that works for you. Some people are good guitar players, who teach, but are not good teachers. Don't feel obliged to stay with an instructor. I finally found a great theory instructor, who took my playing, and understanding to a different level. Yes, I think it can be very beneficial, but you may have to try a few different instructors until you find the one that works for you.
I did a series of one-on-one lessons with a local instructor. The thing it really helped me with was theory. Part of the reason it worked for me was that I had already spend over a year working through GuitarTricks content and had a good solid base to start from. And for learning new songs I think GuitarTricks is pretty tough to beat.
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=Keith
