Well, to be honest, you're right - it is a complicated decision, that's why you get mixed answers. You'll probably get mixed answers here as well.
The problem is, there are both pros and cons for IB and A-levels, and whether you should take one or the other depends on how important different factors are to you.
My opinionI think that IB is always the better choice - however, that is because
I think people should want to study
more rather than less and explore different subjects at a high level for as long as possible, as opposed to specialising too early, or sacrificing depth for breadth.
More objective analysisSome of the number of factors mentioned then:
DifficultyIB is more difficult than A-levels, because you have to do more work - you have A-level equivalents of at least 3 subjects at HL,
PLUS at least 3 subjects at SL,
PLUS Theory of Knowledge and CAS. For some people, this means that they have to 'say bye to their social life', that they are stressed out of their mind, and are unable to get good results as they don't care for some of the subjects (e.g. the foreign language). For others, like me, it's great fun and is very interesting and does
not mean saying bye to anything, or working
particularly hard, just being attentive and engaged. Whether you'll be in the first or the second group, or in between, again depends on a number of factors - how much you enjoy studying and learning in general, how quickly you work, how good you are at switching between tasks; also how good you are at finding and identifying relevant information, how good you are at working smart not hard; as well as, definitely, how good your teachers are, how well they know IB syllabus, etc. So a number of factors there. Just let me clarify though, it's not uniformly bad - again (and I repeat myself because most people on TSR seem to think IB is the worst thing in the world, while other IB students that I know have found it more or less as enjoyable as I did), IB
can be great, and does not have to mean end of social life or your brain.
SpecialisationThen there is also the fact that you can sort of specialise more in A-levels than in IB, although for me, this is of limited relevance as IB HL subjects go to pretty much the same depth as A-levels. Again, some people enjoy this because they know what they want to do, and enjoy doing the subjects they've selected and are good at them. Others like more variety, whether because they like to explore their options, or, like me, because they like learning different kinds of things, both the ones they think they prefer, and the ones that are more challenging but are still interesting.
Results & UniversitiesAnd then there's the issue of results. Loads of people will tell you that universities are unfair to IB students. And that is true - IB and A-level offers are by no means equivalent. A personal example - when I applied for university last year (did not go as chose to do something else), I got an offer of 34 IB points from a AAA-AAB university. AAAa (what people probably get at the end of A-level year) equals 420 UCAS points; 34 points are 479 points. A class-mate of mine had an offer from Cambridge of 41 points (a typical offer), equivalent of 632 points - even A*A*A*A* is only 560 points. And it can be much worse than that. That said, however, this is a concern only if you think you cannot get a good result - so if you say you'll get 30 points, you'll work probably as hard as AAA student but won't get into a AAA university. But if you work smart and know how to get good IB results (e.g.
use the syllabus (!!!) and do past papers), you should be able to get a 36 score at least, and that allows you to get into good universities.
ConclusionSo, lots of different factors at play as you can see. Posters after me will probably put emphasis on one or more of the points above - what you have to understand is though, that this is very individual and, while you must consider others' advice, at the end of the day, consider what kind of person, student and learner
you are, and how appropriate IB is for
you.
Good luck and feel free to post any further questions.