To be honest, the Cambridge / Oxford graduates that I have come across may be smart, but they tend to lack common sense. I spoke to a Law Firm recently about a Law application from Cambridge. He was all good with his education, but he failed on one aspect: common sense.
I don't like the bickering between the two Universities or the whole I am smarter and greater than you because I attend said Universities. It sickens me because you are indirectly belittling others.
It's from my perspective that the most "easily" gained A*s and As come from the science subjects or maths. It's not uncommon for other subjects to creep in I am aware of that, but from my understanding it's primarily science or maths. In those subjects you have to be naturally gifted. I enjoy maths, but I am not gifted and I would struggle at A-level and would fall at around the E-D level not because I am stupid. I have known Cambridge and Oxford applicants to have only maths and science based A-levels. It's "easier" to achieve those high grades in those subjects when you are naturally gifted.
I am more impressed when an Oxford or Cambridge applicant has A levels that do not include Maths or Science. I have more respect for them.