TLDR: Unexpected - Bose A20 are comfortable with great features. But their ANR effectiveness makes them a pass for me. Ratings 0...10 Category.....A20....Zulu 3 Price...........3.......8 ANR............5.......9 Comfort.......8.......7 Controller.....8.......7 Music..........9.......7 Phone.........9.......7 Cable..........7......9 Mic............9.......8 Sidetone......9......8 Isolate........8.......9 Totals........75......79 A while back I purchased a set of Lightspeed Zulu 3's from @pigpenracing. Yes its a plug for him because they were in fantastic shape, he shipped right away with tracking and was great to do business with. I had never tried a pair of Bose A20's and I really wanted to understand the differences. So I finally found a used Bose A20 on craigslist. First things first - this is a used Bose A20. It is the first generation of bluetooth so you can make calls but not stream bluetooth music. I'm guessing it to be about 5yrs old. The telltale difference is that the bluetooth button's icon is a handset where as the new ones have the actual bluetooth symbol. So there is the possibility that this older generation was not as good as the new ones today? With Bose you can swap out the entire plugs, controller, mic assembly with a new setup that does bluetooth phone + music but that is close to $300. Also, it is not clear if that updated module also updates the ANR capabilities. The tests during purchase went just fine. You click on the ANR you can immediately tell its doing something. We met at an airport so listened to the AWOS and did a radio check with the control tower. The last step was pairing with bluetooth and trying a call. That worked great. So I handed him the cash. Now starts the Minnesota winter flying wait for decent flying days. Meanwhile at home, while waiting for flying days I tried out both. I was quickly liking the A20's because they don't clamp as hard, weight less and I like the long mic boom. I also like the controller a bit better. Seems a bit more compact, not as easy to bump the volume buttons, etc. However, when flying the Zulu 3 controller lays in the armrest better and is less likely to flop out. There is a lot of talk about cords. The kevlar cords on the Zulu 3's make then light and way more flexible. I would say the Bose A20 cords did seem pretty solid to me too. I probably don't fly enough to warrant the advantage of the kevlar cords but when paying these prices I think the kevlar version should be the standard. Perhaps the only weird part of the Zulu3's is that the controller is longer / heavier and the kevlar is so thin. I makes we wonder if they might be more prone to being easily yanked out. Trying out streamed or wired audio (music) I think the Bose A20 is a winner. It does sound a bit nicer. I am guessing a bluetooth audio stream on a newer A20 would still be the winner. Finally some flight time! As of this review I have made (3) flights with the Bose A20's. On the first flight when I switched on the ANR after the plane was started and idling it definitely got quieter. Good...so I thought. While taxiing I tested a bluetooth call to the wifey. My first thought was that the call quality is easily better than the Zulu 3's. On the Zulu 3's there a bit of a delay or something that the A20's did not have. Kari said both sounded the same on her end regarding any delays, background noise, etc. But it was the actual flight time that was the big letdown. They are loud! The ANR off the Zulu 3's is definitely more aggressive. With the Zulu 3's I barely hear the Continental 0470 in the 182. But for all 3 flights with the A20s I was continuously wondering why it was so loud. It was almost like I was using a decent passive set. So I would click the power off and WHAMMM!! Now it was mega loud in the cabin. So the ANR is working but just not like the Zulu 3's. On my latest flight a friend rode with. One hour each way. When we landed I said "Greg - what do you think?" He said "They are comfortable but I'd rather wear my nice passive set over these A20's, especially given the huge cost difference." So that makes two of us. Another thing I learned during the comparison is that the Zulu's for some reason seem quieter w/r to sidetone. In the A20's the sidetone was obvious and sounded good. When I went back to the Zulu's I was immediately fiddling with the intercom volume as the side tone almost seemed missing. The last comment is the isolate feature. Both pretty much do the same thing. When you are streaming audio (bluetooth or wired). The normal behaviour is for all ATC and passenger intercom audio to suppress the audio stream. For passengers, especially kids that mode quickly goes from nuisance to downright frustrating. So there is a isolate option where the audio stream and the ATC/Intercom stream retain their current levels. This would also be bothersome except you can then turn down the main headset volume so that the music or movie can be louder. The key difference between these units is that the minimum volume on the Zulu 3's goes lower than the minimum volume of the A20's. So although the A20's would be lighter on the passengers head and perhaps a bit less clamp/pressure - I think they would prefer the Zulu 3's for overall enjoyment of their media. Obviously a modern audio panel is a even better choice but this review is about the headsets and not panel upgrades. Unfortantely the A20's slightly better comfort, better fidelity and slightly better bluetooth implementation are not enough to overcome the key requirement for the headset - great ANR in loud GA planes. As a owner and user of QT Halos I will always use the Halo's for longer trips. For shorter flights (less than 90min) I will happily use the Zulu 3's. For passengers I believe they would enjoy the Zulu 3's over the A20's unless its a short flight like 30min where it probably won't matter either way.