I wonder if I will get a re-call notice?
Well, not yet, but a letter explaining the problem. See
www.Bose.com/A20update for more info. In order to receive this letter, I am guessing that you would need to have purchased your A20 directly from Bose, or returned a warranty card to Bose. I have two A20's and have experienced no problems so far.
Has anyone tried the new Bose A20 directly against the Lightspeed Zulu in an aircraft?
Yes, but this is most subjective and will vary by pilot and acft. In a B407 I find the A20 to be much superior in noise canceling performance, lighter and less bulky. The A20 does not exhibit the low frequency oscillation (rumble) experienced with the Zulu. My audio panel supports Bluetooth, so I have A20's without the Bluetooth option. I sold my Zulu.