Just listening to mine, so very first impression stuff.
Siri
Still pretty dumb but does 95% of what I ask so I'm OK with that
HomeKit stuff "just works"
Not great at recognising tunes with non-English names
Works better than iPhone (not surprising given the mic array)
Quick response
Hears over quite loud music
Feedback sensible/helpful and voice actually not unpleasant
Sends messages from
any voice if the owner's iPhone is on the WiFi network - don't piss off your partner

Sound - after only about an hour of listening.
Amazing for such a tiny speaker
Deep bass and good mid-range clarity and precision
No competition to my B&W floor-standers and Arcam amp - but it's not intended to be
More than adequate volume for a 5m x 5m bedroom
One HomePod definitely wouldn't be room filling for a 12m x 6m living room
AirPlay from AppleTV too low a volume compared to Apple Music
Turning up volume via Apple TV remote results in next Apple Music play being way too loud but this is a problem from app to app on Apple TV and I get it when using my TV speakers too
Software updates required ASAP
Play a playlist/song at a preset volume as an alarm
Play a playlist/song at a preset volume when a HomeKit automation requires it
User-configurable permanent/automagic AirPlay connection from device->HomePod
AirPlay2 (obviously)
Hardware roadmap required please Apple


HomePod XL - around 75-100W should do it so maybe twice or thrice the physical size
HomePod Sub - ditto
Apple TV optical in and Dolby Atmos 7.1 via AirPlay2 to my new array of HomePods
I'll almost certainly get another one to have a stereo pair in the bedroom, and I'l maybe get one for the bathroom.