Paul Winn:
I much prefer the idea of Airplay than Airport Express - no extra boxes, cables and stuff to plug in and connect. But, each to their own I guess!
A separate airport express allows you to position the bs8 in an area without very good wifi reception and locate the airport where you want.
A separate airport express allows you to upgrade the airplay part if apple ever bring out AirPlay 2.
A seperate airport express with the bs8 will be cheaper than the airplay version.
Its still better to just dock the iPad or iPod anyway, for sound quality and battery life.
I just don't get the need to have everything built in