|I recommend these, with a few caveats. Great bang for the buck, though the cost is closer to $200 USD once you add an auto off battery box cord (I believe the $169 has you strap the battery to your headset, and will run down if not turned off).
ANR quality is good, but not as good as the big guys - I finally bit the bullet and bought a Bose A20 this year and haven't looked back. The other major problem I ran into was that, on long flights (typically past the 4 hour mark), I'd start to get a whooping or squeal that required turning off the ANR. They said this was due to moisture in a mic. Taking it off for half an hour to vent out and using the overhead speaker usually brought it back and allowed the ANR to work....but that's not great. Also, features that have become mainstream and standard on the high end headsets just aren't there - ie, Bluetooth for phone or audio streaming, or even just a line in jack for music.
I installed my first set into my old H10-13.4S in 2009, and they were great for the price. One module failed (started clicking) after a season, and their support was fantastic - I'd installed the modules myself, but sent my whole headset back for service, and also asked for a new mic muff. At that point, I was past the 1 year warranty point, and included a CC number and letter authorizing charges up to $150 for repair and purchase of new mic muff. Repair was completed within a week and headset shipped back with new module and mic muff - no charge.
Subsequently, when I started having the squealing issues after I started doing survey work that required long flights, I went back and forth with them, bought new modules as only one side was squealing, sent headset in again...The ANR, at least in my case, becomes useless usually in the 4-6hr window. Often failing to a violently loud and deafening feedback squeal at the most inopportune time.
These modules have their place, and are great for the price. If you frequently do flights over 4 hours, I would not recommend them. If you're typically under that, and taking them off for a bit between legs, they should be great.