Maths is very right and wrong, there isn't any chance for penalty for being too ambiguous and can all easily be learnt by just doing the dozens of past papers available. I don't think there's so many different ways they can ask a question either, unlike Chemistry (and others) they sometimes like to go an odd way around it try and get it out as an application sort of question in a scenario you've never seen.
I just think Maths is much easier to fix and be sure of. I personally hate having to memorise things (like definition etc.) - i'd rather just work stuff out. Don't get me wrong though, I do very much so enjoy Chemistry ;p
I'd definitely say maths is easier. I love chemistry, and it comes more naturally to me than maths, but it is much easier to do well in maths with hard work and practice, whereas Chemistry requires understanding, and contains much more difficult concepts.
i guess its easier to revise for maths... in terms of exams for me its equal... but overall, chemistry is harder to get higher overall a level grade on because they take into account you practical skills ( which im not very good at ).. this is the same for Bio and phys.. BUt i tend to do better in the science, guess i'm more of a scientist than a mathematician.. :P thats the question you should ask yourself.. r u more of a scientist or a mathematician?