Well - I had mine out age 5 and adenoids as was typical back then. My Mum said I never ate a thong before and afterwards I never looked back 
Whenever I have had sore throats as an adult, where my tonsils would have been goes very red, but over the last 4 years - I have had tonsillitis!!! I am currently sat here typing this to you with my throat on fire, spreading up my tongue after a whole night of being awake, feeling like a blow torch is constantly being held to my throat. 
I usually try to hang off going to the docs as not keen on AB really - plus my doctor will only give them out if very necc. But i realise now that once it hits this stage I just feel lousy and know i need something - doc will poss say he's not sure AB will do anything as could be viral, but offers me a prescription to take in a few days time - I feel I now know my own body, I gargle with soluble tablets, take honey and salt mouth washes and nothing helps at all, so off to docs tomorrow I prob get it this bad about once a year (since having DS funnily enough
) so have got appt for tomorrow in the hope I get AB now as feel horrific at this moment and no sleep not helping either.
I feel it's a hard decision to make - I have been problem free for years (am 35 now) and like I say, when I had a sore throat, that part would always be the reddest - it is only since I had DS I have had these problems again. I understand why my parents went ahead with it - I was ill a lot and couldn't eat, but right now, I just want to cry I feel so lousy - still at least it is only about once a year rather than 5/6 times plus a year!
Having said all that I wouldn't want to have the op as an adult either, but whatever you decide, make sure you are very happy with it and no regrets as you make the decision that seems right at the time.
Good luck - sorry for moaning, just wanted to share it from my perspective 