Not only battery life.
For screen, yes, we have agreed, that the rMBP is better.
Maybe even the rMB, too, as there is no argument about the quality of its screen. However, that machine is so underpowered and lacking in specifications, (and ports) that I see it - rather like the 2008 first generation MBA - as something with potential that still needs several further generations of work before it will be a machine worth considering purchasing.
For power, the MBP - and I have had a MBP in the past, great machines, especially when used as an alternative desktop, but a nuisance - for me - to carry.
However, the thing about the MBA is that it hits a sweet spot where power, portability, speed, battery (and indeed, price) all combine.
Different machines are exceed the MBA in certain, specific criteria; but - overall, - when adjudicating and comparing across the entire range of specifications of what make a great computer none touches the combination of qualities which - when, taken together - make the MBA - to my mind, easily one of the best computers Apple have ever made.
I am so impressed by them, that, as long as they are being made, I will have one for travel purposes.