It depends what your needs are. I loved living in Cambridge in many ways, but I used to get real cravings to see the sea and proper hills every now and then. Castle Hill and the Gog Magogs don't cut it - but that wouldn't even be a consideration for many people.
I currently work in Reading, and have lived here (currently living in Basingstoke, because it's cheaper.) I work at the edge of Reading, and it would take at least another half hour of travel if I worked in the centre (except that if I did that, I'd take the train.)
I visit Oxford fairly often. I don't think I would want to live there. I think none of them are great in terms of traffic, but they all have fairly good public transport. They all have good and bad areas to live in.
A lot will depend on factors personal to you - if you have children, what age are they, what type of schools do you want? Do you drive or are you completely reliant on public transport? Do you have a job, or are you deciding between offers? Do you have extended family you like to visit, and if so, where do they live relative to each of these places? Are there sports you like doing, and will there be facilities nearby? A lot of it depends on what is important to you.