I think this is one of the 'horses for courses' things...  Some will prefer one, some the other...

Personally I prefer teaching the Further Maths and IB HL material as for me it is an opportunity to enable students to begin to see what university mathematics might be like, and whether it is something they would like to go on to do...  Also as the material gets more difficult students start to really see the holistic picture of mathematics and understand that algebra and geometry are just two ways of looking at same concept, then abstracting beyond simple algebra to matrix and vector algebra and then on to Group Theory...

I am however delighted that there are people in my department who really love teaching KS3/KS4 as together we form a good team!

Try teaching A level using 'the big idea' principle. As has already been said look at the overarching themes. How do all the topics connect? As all students have to study pure maths no matter whether they study mechanics, statistics or decision maths, (why is it called that, does anyone know?), think about why that is and what they are supposed to gain from their pure maths studies.

When you get down to it the A level exams are asking the same type of questions that GCSE exams do. All students have to do is reproduce certain expected answers and everything works. Very few exams ask questions that cover several topic areas and infact on most papers you can predict what each question will be about. I get this correct about 90% of the time, without reading the paper first, much to the astonishment of my students.