I've used a Zulu for about the last 3000 hrs, mostly airliner but also some quite noisy SEP. Can't recommend it highly enough, so much in fact that I've just treated myself to a Zulu 2. They're extremely comfortable and the noise attenuation is superb. Most old bold pilots I know have hearing loss, so a quality headset is a sensible investment. Also I never really appreciated how fatiguing constant background noise was until I tried these and the ANR reduces it to almost zero.
They are expensive but if you do enough hours it is a small price to pay. Lightspeed Sierras might be worth a look as a cheaper option.
One consideration is that with good noise attenuation you do lose some audio feedback from the aircraft such as the sound of engine speed, rotor RPM etc, however you do get used to the new levels quite quickly.