Eton is a fantastic place. There is no need to keep comparing with other schools, all of which have their own strengths.
The boys who go there are bright, on an absolute scale. The do a pretest in Year five, which excludes a lot of boys who may be "doing well" at school but are plodders. The CE pass mark of 70% is challenging too, even to those with high IQs, although, in reality, hardly anyone fails the CE.
A boy does not have to be "driven" to survive Eton. The only time this is tested is when they are interviewed at their pretest - a bit early to assess their drive. The main criterion for surviving Eton is to be happy with boarding, and this is tested in the two years they spend in prep school. Other than that, it has the same routines as anywhere else.
A boy who will thrive at Eton is someone who takes advantage of the special/extra curricular things that Eton has to offer that few schools can match. Many boys are content to just do the academic part of school and not get involved in the top class sports/drama/music, or to be involved in clubs.
I have always been amazingly impressed with Eton boys. The main thing that always strikes me is how incredibly polite they are. Then they can hold a conversation on virtually any topic with an adult.
If I had the money, I wouldn't think twice about sending DS2 there, but I wouldn't have sent DS1 as he wouldn't have liked boarding.