^^^I see the benefits in respect of kids from an early age being able to develop technically sound strokes more quickly and having more fun being able to actually play the game on an appropriate court, although I disagree with the mandatory age groups that we have had here for about 5 or so years and the ITF are pushing worldwide.
Robert is Robert - he has his system, which has been successful in the past and could well be successful again - but maybe if he adapted to using graduated equipment he could be even more successful. Peter likely hasn't coached any under 10 tennis since ROG became more widespread.
Whether ROG systems have long terms benefits is a bit of a moot point - as everybody has to do it now (if they want their u10's to compete anyway)!
Not really empirical evidence, but here we have the strongest crop of juniors we have ever had at one time (most of whom grew up using graduated equipment).
Don't be upset by the results you didn't get from the work you didn't do...
talkcoaching on wordpress, come check it out :)