The morning glory on the aptitude tests is they are difficult but you can practice, go to any of the good book shops and look up the tests books there are loads. Get ones that are focussed on the ATC aptitude tests i.e. 3D awareness Command decision making and maths. Test yourself and push yourself, but the bottom line is it's easier if you have the aptitude. If you're serious go to a AFCO and ask they'll put you though the aptitude tests that they have and will then do all the rest to get you in if you have the test results to go for the aptitude tests.
One you pass then you have to do the Cranwitz time and show you can be an Officer. Post that you then go to SFC At RAF Boulmer and do the ADFC this decides using simulators if you'll e a systems or controller or go back to Cranwell.
Both sides of the job are interesting but for different reasons, the Control side is an adrenaline rush. The bigger the sortie the better! But you have to be able to control safely as well as tactically and that’s what stops most people going for Controller(WC). The Systems side is more technically orientated especially after your first tour as an Identification & Recognition Officer(IDRO). The trade comes back together at Sqn Ldr rank when you do your Master Controller ticket.
In between time you can go E3's Travel the world and normally stay in hotels, but more often live in tents or stay on base. Or go 1ACC where you'll definitely stay in tents but travel about the same. All through these tours you will still be an Officer responsible for a certain number of troops, their welfare discipline and career development.
As for is the job rewarding yes it is and if you put 100% into the job then it can become even more so. No you don't have to be a Spotter and know everything about aircraft, but you are expected to have a working knowledge of aircraft peformance and tactics.
Will the RAF ask you in with the urrent state of recruitment, probably as the branch is always short of WC's and IDRO. The rest is up to you.