I am aware of M1D Black but have no idea on what the reviews look like so far. Here is my train of thought to this question.
If you can gain X amount of muscle on cycle, how much would you realistically get if you added AnaBeta? Stronger substances would be more likely to render AnaBeta obsolete because you wouldn't be able to expect much more hypertrophy in the given time frame to make it worth it. Lighter cycles would probably yield more reward. Hypothetically, if someone gained 10lbs on Superdrol (I know this isn't the substance in question) would Superdrol + AnaBeta = 11lbs or more?
Contrary to that, if you gain 10lbs on a Superdrol cycle and think you will lose 5lbs during and after PCT, would AnaBeta during PCT help retain gains and leave you with a higher net gain from your cycle + pct?
I think the latter is the wiser idea. I am being completely speculative and others may chime in with personal experiences but AnaBeta and M1D Black are still new additions to the market so nobody is likely to be able to answer this definitively.
Ben