I ran using JD two years ago, then our coach had to leave. I saw great successes from it, but the program and my coach were very strict on pacing. I was a junior in college, we never ran faster than 7 minutes/mile on our easy days, and we trained 7-8 hours a week (typically included an hour of cross training, and all runs were singles).
Our coach used a strict, organized progression for T and I pace. T pace we would start at 5x4 minutes with 1 minute recoveries. As the season went on, we would move up to 4x5, 3x7, 2x10, 20 minutes. Typically this was done in the early season and we would keep the same pace for all of the workouts, until we had a race and then our vDot would move up. Workouts were extremely controlled, we would have a 100m strip every mile or so to make sure we were on pace. The 20 minute T pace is straight from the book.
I pace went - 15x1 on/1 off, 10x90 on/90 off, 8x2on/90 off, 6x2.5 on/90 off, 5x3 on/90 off, 4x4 on/ 2 off, 3x4.5 on/ 2 off. R pace were typical workouts straight from the book (you get the picture from the previous ones I have stated). Again, very strict on pace to make sure that we were not going too fast. I pace was never more than 10k. Every Thursday we would do a 30 minute run and 30 minute pool workout.
We did weight circuits twice a week as well and shifted into plyometrics later in the season.
Our coach was a former triathlete and it was his first time coaching cross country and track. Looking back, it seemed like sub maximal training but there were definite benefits from this style of training and once I am on my own, I will do this style of training again. I know that these workouts aren't right out of the books, but he did use the charts for our paces and used the book as a guide.
Overall it is a good program even though it is a little cookie cutterish. If you follow the paces, there's a good chance that you will never overtrain and the workouts are setup to show progression throughout the season and I think that seeing the progression built me up mentally as well as physically.