Yeah, I have no idea what he is talking about, I have two AirPort Expresses, and an AppleTV, and AirPlay is the only wireless audio protocol I've yet found that actually gets the audio sync right, every time.
Not every time. Maybe on Apple-only hardware (although I think audio from games wasn't synced perfectly when I tried with AirPort Express).
But if you use audio equipment with licensed AirPlay made by companies who don't get these computers thingies, such as Philips or Marantz, it's worse. My Marantz AV receiver introduces 6-or-so seconds(!) of delay into music playback and that's one of the better ones.
I use AirPlay from my MacPro over wifi to a Klipsch Gallery G-17.
With iTunes, it 'just works'.
With AirPlay as the default 'Output' sound for the whole OS (new in Mt. Lion I think), it definitely has sync/delay issues. The delay is nearly 2 seconds for something (like hitting 'vol up' on the keyboard).
