Murphy Henry does a great job in teaching. I still prefer her cassette tapes for learning. As a whole I don't like videos I can listen to a cassette in the car or take it with me when traveling - you can't do that as well with a video, but to each his own. But for learning bluegrass banjo I found Jack Hatfield's Bluegrass banjo method (with the cassette) to be more helpful. He uses tab but he highlights the notes in the melody so you have a better understanding where it all fits into place. But I must admit I Frail the banjo mostly. I find frailing easier to understand & I was able to apply it from the beginning. I will still tinker around with the bluegrass style but it isn't what I use when I perform or jam.
Good luck, Charcloth