I've taken a total of about 6 or 7 golf lessons in my life from 3 different teachers.
One guy was more of an old school teacher, but a good one, he could also play (shot mid to high 60's, I knew he was a player...he could actually play right and lefty)...
The next guy was the Head Pro at my club. He was not a great golfer, he shot in the high 70's, low 80's. He wasn't awful, but wasn't really what I expected from a teaching pro when I played with him. He was not a good teacher either, I learned absolutely nothing.
The guy I work with now is a golf magazine top 100 teacher, and I can see why. i've taken two lessons from him and i've improved so much it's incredible. He's completely got me from going from a high, fade/slice with no distance to hitting the ball on a low, draw/hook trajectory and added about 10 yards to each club, and 15 yards to the driver.
The guys with the resumes, I've found in my experience, really have that top 100 tag for a reason. He can just explain it to me and uses the video software to the point that makes changing my swing rather easy.