I do Biology,Chemistry and Maths and going into A2.Personally I find chemistry the easiest and maths the hardest.
Chemistry is mostly about understanding concepts and applying your knowledge especially in organic chemistry.It is not really about memorisation.I don't find the maths too challenging and many of the maths questions are a great way to get lots of marks. Organic chemistry is a bit hard because some of the examples are hard and you need to really think as you never seen such examples before and have to try and apply your knowledge.I found chemistry only hard for the first month but after that I just started self teaching myself and watching machemguy and doing questions and it was all good.I really enjoy chemistry personally and don't find it too hard.
For Biology,it is all about memorising content but you also have to understand it as you have to apply knowledge to different contexts.The mark schemes are a pain,you have to memorise the mark scheme,because it is very specific about using particular words and phrases,so sometimes when you know a topic well,you still don't get the marks if you didn't word your answer the way the examiner wanted you too.Some of the topics take some time to understand especially some of the processes, I find concepts in chemistry a lot easier to understand compared to biology where I have to sit there and look at 5+ different resources about one thing and think about it for some time before things click.Some topics are quite interesting,but I find plants extremely boring and hate any plants related topic,but the human stuff is interesting.