I have been on both sides of the fence as an area trainee posted to TC where I managed somehow not to validate. I was subsequently posted to a tower only unit (which new guys n' gals won't be able to do as area studes do no aerodrome course (what numbskull thought up that one ?)) where I am now valid and very happy. But, I was desperate to do area and TC was a fantastic experience despite the disappointment of not getting through. Aerodrome control has different challenges but don't let the area boys tell you it is any easier. Aerodromes have their own challenges and whilst (unless you are somewhere super busy like heathrow) you wont be working flat out all day, your busy periods could well match up with the workloads that the AC boys have to endure. Also bear in mind that of the 12 aerodrome/approach bodies trained up every year, six of you will be going tower only, no radar.........whilst this isn't a problem for me at the moment, radar is AT LEAST half the fun of the job. Looking out of the window all day is one of the joys of my job along with being paid a not inconsiderable some for doing something that I love.
At the end of the day, the truth is that they will send you where they think you will be best suited and while you may be asked to express a preference, it counts for little. So....take it on the chin and make the most of it. This is without a shadow of a doubt one of the greatest jobs around with tremendous job satisfaction whichever way you go.
Good luck.