I don't know if the comments about the OTC are banter or a blinkered view of what the OTC does by RAF types who don't understand what it is there for (difficult to tell out of context). It pays roughly £30 per day plus college to place of duty allowance with a bounty of about £250 per year. It isn't all about digging ditches as you spend about 50% of your time doing special-to-arm training after you complete MTQ1 (basic soldier training). Depending on the size of the OTC you will have the choice of RSigs, RLC, RArty, RE, REME, Cav, or Inf sub units to choose from. Many of the functions of the Combat Service Support elements will have a cross-function with other services (e.g RLC does a similar role to AD/Movements) that provide training which will be useful in a GB role in the RAF. Not to mention the MTQ2 syllabus which focusses on leadership and the ability to take a command appointment in your 3rd year which develops leadership skills. You also get to see the all-arms battle in the final phase of annual camp as the sub-units take on their roles against an enemy.
My advice, if you want to be aircrew and are going that way anyway, UAS is a good bet, if you are heading for a ground branch and aren't that hung up about spending 3 years away from the RAF and want to broaden your horizons a bit then the OTC probably has a lot more to offer.