Edexcel Or Cambridge for AS and A-LevelWatch
I asked my teachers at my current school (we do CIE for both IGCSE/A-levels but I'm changing school since my school does not offer chemistry A-levels).
Teacher A who is the head of secondary and teaches maths/physics said: "They are the same, just different style"
Teacher B who is the co-ordinated science teacher (teaches three sciences at IGCSE) that studied Biochemistry mainly at University said: "They are the same, just different style (again)"
Teacher C who teaches History, Business Studies and a bit of Geography said: "I have a friend in another international school who is a history teacher and he told me that CIE History is harder than Edexcel History, and CIE is harder to achieve A than Edexcel so his school changed History to Edexcel. Business Studies seem to be the same but I don't know about other subjects because I don't teach them."
By looking at exam papers....I don't see much difference but that's because I'm still Year 11 and have not started A-levels yet. It is clear though, the style of questions is very different. In theory, there should be no difference in difficulty though. It wouldn't make sense if one was harder than the other but the qualification is same "A-levels"...if one was easier than the other then it would be unfair in university entrance. I don't think they would bother about which exam board you took...there are thousands of students applying and who got time to look at exam boards ._.