They are both kinda right.
Basics: Angle of attack, the angle that the air flowing into an airfoil
makes with respect to the line where that airfoil would make no lift. (the
line through the airfoil where the airfoil makes no lift is called the
zero lift line (ZLL).) So angle of attack is the angle that the incoming airflow
makes relative to the ZLL.

Measuring angles with respect to the aircraft, the ground, the rotor shaft is
all kind of waste of time. What matters is the angle with the local airflow on
the airfoil.
Here is a diagram for the advancing blade.
The local airflow is the sum of the rotation and movement.
THe blades sees +10 degrees. The lift is roughly 90 degrees from
that, the part of the lift that is tilted forward makes the blade move, overcoming
drag. The other part of lift is what lifts the aircraft.
mickey