smallfries,
Firstly, congratulations!! I have also just passed OASC, possibly the best feeling in the world. However, I'm in my final year at uni (last exam tomorrow - possibly should be revising!) and, in reference to your question, I'd say go with whatever your gut instinct is and whatever route feels best to you.
Personally, I've had an amazing time at uni. I've been on a UAS for two years and have been given such an array of different opportunities and experiences through this that I wouldn't want to have missed it for the world. As I'm sure you know, bursars have to become members of a UAS, you get the opportunity for 'free' flying, meeting people from every area of the raf, every kind of sport and expedition imageinable (we have been dog-sledding in Sweden, hiking in the Grand Canyon, skiing in France etc.). You'll also get that additional money every year.
However, I'm also doing a slightly 'mickey-mouse' course (theology), and therefore have tons of time on my hands, whereas engineers definitely don't.
As I said, in the end, weigh up both options and go with what feels best.