I teach IB Maths and would like to refute some of what shootingstarz has written.
"IB = taking more exams, less depth, having to be good at all subjects in order to gain maximum marks, taking subjects that you don?t enjoy, UK Unis prefer home grown qualifications, less time for friends."
Yes you do have to take more exams, but do not be deluded that they are to less depth. It is generally acknowledged that Higher Level IB Maths is more rigorous than A' Level, and possibly less so than Further Maths.
It is true that you may end up studying some subjects for longer than you might wish.
I do not think there is any evidence that Unis prefer home grown qualifications. Every year we have plenty of UK uni's visiting our school trying to encourage our students to enroll with them.
I'm not sure what is meant by 'less time for friends' in this context.
A levels= taking 3-5 subjects that you really enjoy, more in depth knowledge of chosen subjects, more time for extracurricular and friends.
I have already covered the in-depth sthing. An integral part of the IB Diploma course is completing CAS hours, i.e. Creativity, Action and Service. So music, sports, voluntary work are all actively encouraged.