teleplayer, my humblest advice;
If you think you are able to perform well under stress condition and you are the studious type of person, by all means you should go for JC, really. The reason I backed out is stupid..lol..I was afraid of screwing up the A level and the way I study really depends on my mood. What if I just don't have the mood to study for A. Die! Not to mention that I am a last minute type of person XD
Poly is totally different lifestyle compared to JC. Some poly like RP and TP have bands as a CCA, that's really helps you if you really keen on music. However, considering poly's way of studying is on your own, you have to build up your discipline, it'll be good to your band too if you have that level of discipline.
If you are considering a degree in a local uni, JC no doubt offers a better placement than poly and it takes 1 year lesser to complete.
Always secure or find the right circle of friends, if you mix with the wrong kind it really give a whole different story altogether.
Man, my bad.. I talk alot, sorry..lol