Depends from person to person I guess. Personally, I found A level Maths quite simple, ditto most of my further Math modules barring FP2 and S4 which I found fairly challenging. The Economics A level was alright too, just horrifically mundane and I learnt nothing - its just about pattern memorization - which is the main issue with the basic Math modules as well.
On the other hand, I got my ass handed to me by AS level Chemistry, barely getting an 80 average across my AS level after an insane amount of work. Infact, I probably worked harder for that AS level than any of the 3 full A levels I did combined, because I just couldn't get my head around the stuff!
I can see how a lot of the super-smart folk on here (TSR on average has a far more academically able cohort than the general public) find them easy - there's blokes on here who've barely lost 10 UMS across 12 modules in Maths and Further Maths, and there's a LOT of them.
Overall, I think A levels are alright, just the exams should be a little less repetitive in terms of testing. The C3 paper for example, though quite difficult by normal standards, it was across c1-c4, m1,s1 the only exam that kind of tested any mathematical ability, and in the end the low boundaries hopefully enabled people to make the grades they needed for their offers. Maybe the testing should just be made more difficult so as to properly determine whose really good at a subject and whose not.