Ok I am a hack cyclist and anything I say is pretty subjective, but I feel that the MARC PRO device does help with recovery IF:

1. You use it for long enough and at the right setting. I found I felt better the next day if I hooked myself up for an hour, not 30 minutes as many describe. I also found that I can tolerate different amounts of stim depending on the soreness present in my legs. In my opinion you need to set the stim to as hard as you can without feeling pain. No weak sauce allowed.

2. You flush your system with a big tall glass of water or two after the session. Just like after a good massage.

3. You combine it with foam rollers and other recovery techniques (sleep and the natural HGH pop you get from sleep)

Too many people are looking for magic and the MARC PRO is simply another tool. It probably helps flush crap out of your legs, certainly with less stress and energy expenditure than a "recovery ride". Is the only tool or the best tool? Don't know as the research is incomplete and I haven't tried them all.

YMMV