I am an extensive Squeezebox user and Spotify really is at a competitive disadvantage to MOG, IMO.
The MOG app really is vastly superior to the Spotify native app. I've had nothing but problems with the Spotify native app on Touch and radio devices; it doesn't even work on legacy devices. Searching always returns null queries, etc. Spotify 3rd party app is ok, except that you have to have your local server on all the time.
MOG, on the other hand, works with all Squeezebox devices, can run reliably off of mysqueezebox.com. MOG, for me, has better value.
It pains me to say that because I like Spotify's interface, but Squeezebox support has languished and is ultimately going to be a dealbreaker. Are there any moves on Spotify to make Squeezebox support better?