Quiet Mason
I'm currently in my final year at Nottingham and have been on the UAS (EMUAS) for two years.
Firstly, joining the UAS is not too difficult providing you put a lot of work in. Selection is through an interview broadly based on the OASC interviews, so make sure you know all about RAF, current affairs and yourself (?!). The first step for joining is to seek out our stand at the Fresher's Fair in your first week.
I would highly recommend joining a UAS, it offers you a chance to fly, go all over the world on exped (there was a dog-sledding exped to Sweden recently - I've been lucky enough to get on expeds skiing in France and hiking the Grand Canyon). On top of that, the Entertainments side is amazing, with a number of big formal events every year. You are expected to attend a Tuesday night 'Town Night' every week, in which all admin is sorted and you are given a lecture by someone connected with the RAF (FJ pilots etc are fairly common). Also, it gives you the chance to meet a whole load of like-minded people and EMUAS is based at Cranwell so you meet lots of officers who have just been through the IOT process.
In terms of selection, the UAS gives a lot of help with the application process, as Inaspin says it cuts out the middle-man.
I've had an amazing time on EMUAS and, as previously noted, would highly recommend the UAS system to anyone wanting to join the RAF who is prepared to put in a bit of time and effort.
Hope this helps!!