I don't think they're worth it, but many will disagree with me. My chief complaint is that they can't deal with high-frequency noise effectively, & often have a lower NRR than passive headsets when the ENC is turned off, thus the high-frequency noise is worse with them than with a passive headset. Perhaps not true for all models, but in any case make very sure the passive NRR is at least in the 20+ dB range. I've tried ENC, and they work really great without the engine running, and to filter out the main rotor noise, but that isn't the noise that will hurt your hearing. Stand outside the helicopter, unloading passengers with the engines running, & see what I mean. The ENC will be much louder than a good, well-fitted passive headset. You could wear earplugs with it, but then what's the point of the ENC?