I recently bought a Bose ANR headset and I traded in my David Clark 13.4. The Bose unit is very well designed and I am certainly very pleased with it. The big difference that I notice is that if I was flying for over an hour with sunglasses on then I would feel some discomfort due to the pressure of the ear cups from the DC headset. I don't have this problem with the Bose unit, which is the most comfortable headset I have ever worn. I have not used another type of ANR headset so I can't compare but I find the Bose ANR very effective. The Bose unit is not cheap so it is probably not worth it for a PPL who might not fly that regularly but for a professional pilot then an investment in a Bose headset would be money well spent in my view.
Cheers