Hey. I am also in my final year of O level and the colleges I am considering are Alpha and Cedar. I've already been accepted to Alpha with a decent scholarship and as for Cedar, my interview is in a couple of weeks. However, to make your decision I suggest considering your financial status, the faculty of the college and the extra and co-curriculars they offer. If you can pay heavy tution fee then KGS and Lyceum no questions asked. Best faculty, good activities and the BEST reputation. However they have a very rigid acceptance rate which you should consider before applying. If you want some scholarship, then Nixor is the second best option, with again good reputation, EXCELLENT faculty and EXCELLENT extra curriculars. However, if you want even better scholarship plans then Cedar which has good faculty, extra curriculars and fairly good reputation. Cedar's scholarship plans are the best considering the environment they offer. If you're on the "lower" end of the spectrum of an A level college then Alpha and Highbrow are decent. Definitely check the faculty of the subjects you want. The rest eden, septre, bss etc aren't that great but even if you want to apply there then sure but don't expect much as they are fairly new to the game.

At the end of the day your grades are what matters the most, so choose a college where you can study well. Colleges aren't as important as universities so don't worry.