for Edexcel maths, we couldn't take exams in Jan which was pretty difficult but Idk if it's there's a difference with other boards or if that's a determining factor with the new linear maths. for AQA physics I find it pretty difficult and loads of contextualizing with the new spec but idk if that's not the same for other boards. for Edexcel chemistry, I find it pretty enjoyable but I'm pretty sure Cambridge Pre-U has some interesting topics we don't tend to learn about at A level, like Van Arkel triangles and other such things. Also with Cambridge, they have a grade (D1) which is supposed to be better than an A* so could potentially in the future be viewed as one.