I just completed the training plan for mtb intermediate; I followed it in order to compare the results with the plans I have followed in the past. The verdict is that they need to be improved. The last 2 weeks are too light, so you lost some shape there. Using my training graph for optimal training, fit condition, took me to the fresh section since the week before the competition. Last week it was only a recovery 1hr session 4 days before the race. Because of that at the race I was lacking aerobic condition. The force on the legs was there but I feel exhausted. With other plans that was not the case.
Also, at the middle of the plan the workouts were not updating on the calendar, because there was a bug. I had to create a dummy workout to let them refresh.
Having these plans is a good idea, hopefully garmin improve them in the near future