Hey Mate,
Well i'm in a similar situation of not being able to decided between the two.
I think with the introduction of the new Thomsonfly scheme at Jerez that the school is starting to show its worth amongst the airline community. A positive sign and i think the prospects of getting a job are good as time goes on there.
Granted oxford do have good contacts and manage to place plenty of people with jobs but there are a lot of people going through oxford and i'm not so sure the proportion of jobs to qualified pilots coming out of there is as great as everyone thinks. That said, if you pass your skills first time and get good averages you'll be chosen first so there is a very good chance you'd get a job.
In my personnel opinion i prefer oxford purely because they do the ground study all at once and get it out of the way. I believe jerez, although correct me if i'm wrong, do six exams whilst flight training which can be tough to do both at the same time. The oxford scenario therefore suits me and is the one i'd recommend despite the 10 grand diff!!!
Hope this helps, good luck with the whichever you choose.
Taiguin