Here are 3 of my recent answers on r/sonos on reddit:
followed by:
and this one on speakers:
I recently moved from a purely Sonos-based setup (14 rooms) to a hybrid WiiM/multichannel amp + WiiM amp setup, and unless you have needs for high-end amplification, I think the pure WiiM Amp-based setup (or WiiM Amp Pro, if you don't need Airplay) is the way to go. I've learned the hard way on this one. Multichannel amps (I've used Rotel, AudioControl, Sonance, Lexicon, and Buckeye multichannel amps) all seem good, but there's always a little funkiness that goes along with them. Individual amps require more wiring and maybe a bit more rack space, but save a lot of other headaches. Most residential rooms won't require a lot of watts to enjoy.
The real question is budget. Think about how much you want to spend on speakers first, then amplification. The streamer cost is fixed and WiiM has set the benchmark in this area. A potential way to think about amplifier cost is cost per channel (or cost per 2 channels / per room). Right now, the WiiM Amp is $300 on Amazon. A WiiM Pro is $150. (You definitely want to use a wired setup, btw. Wires are your friend.) So, your cost per room for amplification is $150 per room ($300 - $150).
The
Crutchfield OSD 8 zone amp is $125 per room - $1000 / 8 rooms. That's not bad, but you're pretty locked in to playing the same music everywhere. Ever have guests? Want to play at different volumes in different rooms? If want to add streamers (WiiM or Sonos Port) later, your per room cost for Sonos will be much more. Also - your quote only has 1 source in it - the Sonos Port, or the 1 additional amp cost is off -
a Sonos Amp is $700, not $150.
So, if you look at the expansion for any future growth, it looks like this:
Base Sonos system - 2 sources + 18 channels/9 zones -> OSD amp ($1000) + Sonos Amp ($700) + Sonos Port ($450) = $2150
+ 1 more source - above ($2150) + Sonos Port ($450) = $2600
Base WiiM system - 2 sources + 18 channels/9 zones -> $1000 + WiiM Amp ($300) + WiiM Pro ($150) = $1450
+1 more source - above ($1450) + WiiM Pro ($150) = $1600
Bottom line is that you're going to have much more flexibility and lower cost with a WiiM-based system, assuming you're focused on in-wall / in-ceiling speakers.
My take? Wire up all nine zones with speakers, but no amps to start. Play around with 4 or 5 WiiM amps to see which areas you're listening to the most. E.g., no bathroom, no closet to start. Then, either double-up some of the speakers to either be in the same zone (e.g., group Main bedroom / closet / bath) and go from there.