Is it more impressive getting into Cambridge or Oxford
They are roughly the same, depending on your courses obviously. Cambridge is famous for NatSci, Oxford is for EM, PPE... Impressive to go to either of them, or actually if you want to be super ultra impressive, go to both. You got undergrad, master, phd to go
Is it more impressive getting into Cambridge or Oxford
Depends on your course. But really, both are highly respected and if you're choosing between them, you should worry more about which course you prefer and where you'd be happiest.
Is it more impressive getting into Cambridge or Oxford
This is my personal opinion. I think getting to Cambridge is more respected.
I think Cambridge gets people that are brilliant in a particular field and deepens that field, but Oxford gets people that are overall intelligent with general success.
It is the reason why Oxford grads are probably likely to be world leaders or CEOs while Cambridge grads to be Nobel Prize winners or genius-level intellectuals.