I left there 21 years ago, I obviously can't tell you what its like now, but it was very good then. Used to be lots of discipline but lots of fun (probably no discipline now as with most modern schools). As long as the child is a good worker they should do well, as the school has a good record academically. I still go back there once a year when I can and meet up with lots of other 'Old Boys', who have done quite well for themselves.
I spent 5 years at DYRMS, leaving after my sixth form in 1992. Went on to university and then to Sandhurst. Enjoyed many things about the place, especially the sports and adventurous training opportunities that many school children never get. The cadet force started my interest in the Army - and now I'm a major in the real Army! I work with two other ex-Dukies, also majors, and I've met plenty during my time in the forces. That's not to say everyone does join up but, from my era, about 1 in twelve seem to have done so.
The academic standard was fairly good while I was there. At least two from my year are now surgeons and many others seem to have very good jobs in the real world.
The boarding houses are small enough to have a good atmosphere (about 50 children per house divided into year groups of 13-ish each).
PM me if you want any more info. I would recommend it - I have a one year old girl and have begun the battle with my wife already!