Our choice was between RGS & John Hampden so DCGS didn't enter the equation, but maybe my thoughts will help. We chose RGS for DS1 (Y9) and will do so again for DS2. The school just felt "right" and we think it will suit both boys. We have found the care and dedication of the staff to go beyond the call of duty on many occasions and nothing seems too much trouble. I think academically RGS and DCGS are very similar so it boils down to a gut feeling when you visit the schools - bearing in mind that open evenings are really just a marketing tool
. Which one did your DS prefer - after all it's the next 7 years of his life! Have you seen the schools on a normal day when the boys are around - seeing the way the staff and boys interact, behaviour at class changeover/lunchtime/break? Does one of the schools have a subject/sport/activity that your DS is really keen on? Which one is easiest to get to?
Good luck with making your decision.