I use TrainingPeaks Premium and highly recommend it. Works great. I am a slave to the Performance Manager chart. I don't have power, but I can easily see improvement or lack thereof on my resistance rollers. IME the single most important thing one can do vis a vis training is to modulate the training impulse. Almost doesn't matter what else you do as long as you can precisely control your training dose and hold it somewhere near, but not over, your capacity to absorb same, from day to day, week to week, month to month, and year to year. I use both the PM chart and my morning resting and standing HRs to accomplish this.