I have found AG hair a bit easier to deal with. I'm not too familiar with my generation though...it might be easy, too.
The AG hair is very conducive to hair styling. A knockoff may have "bald spots" as they may not use as much hair on the head. It will look full, but then when you begin to style... That would be something I would certainly check.
The only thing that bugs me about AG: I am not too crazy about the dangling string up by the neck. I kind of understand why they have it. And one more thing--the cloth body versus the non-cloth appendages and head. They look funny in a swim suit to me.
My kids don't mind though.
I also like that if there ever is an issue due to lack of care or a mishap, you can send the doll back and pay to have the part repaired or replaced.
We have replaced 2 doll heads. One because Josefina's hair just got too bad from lack of care and the other was a bitty baby who lost an eyelash. Although that may have just been an eye replacement. It has been a while and I forget.
It is better of course to just take care of the doll, but it is nice to know that a beloved doll can be repaired and have parts replaced if needed.
ETA: For the hair--it is helpful to use a wire brush as suggested and to invest in the hair pick they sell. It really helps to get tangles out should they occur.