So, I am nosey and whatnot and I asked around my office. These are not anything I came up with, just what the UK people have said.
In general, both have pretty crappy houses, that is just the way it is in places with lots of students. But since Oxford is bigger you can get out of the city and still have transportation options aside from needing a car. Most of the villages that are only a few miles from Cambridge have appalling bus service, if it hasn't been completely cut in this last round of changing schedules.
This was the general run down:
about the third of the size of Oxford
has more open green spaces
has more of a centre (although almost all the housing in the centre is student only)
less of an industrial ring outside it
More trains go to London
Does have cheaper housing
More causal than Oxford (?)
Has way more housing options because more people
Much much better public transportation
Fewer trains to London, but all get there in an hour (whereas the slow train from Cambridge can take almost 2)
other advantages that come with a larger city, more stuff to do
The big thing that stands out for me, if you are only going to be here for a few years (not sure of your situation) Oxford has much better links to the rest of the country than Cambridge.
Every time you want to go somewhere, aside from London Norwich and some places in Suffolk, you must go through London and then get on the underground and then go to another railway station and then wait for another train.
So if you want to really get out and explore the country, which if you are only here for a short time and you won't have a car, then Oxford is a much better bet.