Agreed with above reply. I bought a pair of zulu ones at the start of my flight training, and haven't looked back since!
If you start a flight without the ANR working, you can usually tolerate them fine, if your batteries die midflight, the noise difference is significant. I usually have a pair of AA lithium rechargeables in mine, and they last usually about a month.
Thy are designed to work best with the ANR working, and provided you carry a spare pair of batteries, or recharge them not long after the light flashes red, everythings good. After a day with 6-7 hours flight time sitting in a noisy piston, you want to have ANR.
No I don't work for zulu, but mine have worked very well for me for over 4 years, and would happily recommend the 1's to anyone.
(Just don't ask me about the bluetooth, I've never used it)