Face..there is very little audible difference between a neodymium and ferrite magnet. It would mainly apply to air chamber differences. Neodymium became the rage in the 90's due to there higher magnetic flux, and the ability to move current three times faster than ferrite. China currently has a monopoly on neodymium, and it is far more costly than ferrite material since its a rare earth metal. The main benefit is that less mass is required with neodymium than ferrite, resulting in a lighter, more compact driver.
Large ferrite magnets are like capacitors, and can handle larger voiumes of continuous current. The tweeter in the Sony's have a maximum rms rating 0f 90 watts. The tweeter in the Aerial 7T can handle 200 watts rms without breaking a sweat, due to there large magnets and there one inch copper voice coil. Neodymium's overheat more easily than ferrite, so avoid clipping your amp. You will destroy a neodymium if it overheats, which is not a problem with ferrite.
Large ferrite magnets are like capacitors, and can handle larger voiumes of continuous current. The tweeter in the Sony's have a maximum rms rating 0f 90 watts. The tweeter in the Aerial 7T can handle 200 watts rms without breaking a sweat, due to there large magnets and there one inch copper voice coil. Neodymium's overheat more easily than ferrite, so avoid clipping your amp. You will destroy a neodymium if it overheats, which is not a problem with ferrite.