When I was on Windows Phone, I used Phonos as my Sonos controller. Sonos had been working with Microsoft on Project Phish, which was eventually cancelled after two years, so there never was a modern Windows controller. I believe that the desktop controllers are seen as legacy at Sonos since they have not seen any significant updates in years.
This opens an opportunity for third party developers to fill this void. Andy Pennell is the developer behind My Speaker, which I wrote about yesterday, and also wrote the Phonos and Phonos Universal controllers. I also learned that he had worked on the initial implementation of Phish. This means he knows what he is doing. He may not be the greatest designer, but his stuff works.
When trying Phonos Universal I found an interesting anomaly: I had a third Spotify account showing up. As it turns out you can take a look at the accounts your Sonos knows about by replacing the IP address in this URL (http://192.168.1.4:1400/status/accounts) with one of your Sonos players. This third Spotify account was from a friend who had used Spotify Connect at my house and Sonos kept a record of it. Since it was surfaced through Phonos Universal , I tried to use it and it was live. Apologies, Alex, if I interrupted your session at home. I reported the issue to Andy and he will hide these accounts in the next update.
The other thing I found out when looking at my accounts is that Sonos keeps a record of all deleted accounts. I will let you know why they are doing this, if I can find out.
If you use a Surface or any other touch enabled Windows 10 device, I recommend you buy Phonos Universal, if only to support a great developer.
I started with Phonos in the past, but last half year I switched over to Zonos which is another alternative from the Microsoft Store delivering a Sonos native Windows Universal App. I think at this moment Zonos is the better alternative with a lot of regular updates and an active user community around it.
https://www.microsoft.com/en-us/store/p/zonos/9nblggh4q9wz
I have bought both Phonos and Zonos and both are currently installed on my Surface device.