@Revolutions So that places them pretty much at price parity, doesn't it? I haven't listened to a Node 4 and really I can't compare my Icon to my Ultra as they're just in totally different setups.
If you're using Spotify Connect rather than BluOS or the WiiM UI then really there's not much in it in terms of usability. I'm sure each has relative pros and cons in terms of inputs / outputs / compatibility etc. but a straightforward use case like yours renders that stuff irrelevant.
I find my Bluesound is rarely a bit unreliable with being recognised on my network. That could be entirely a network rather than Bluesound issue, but my Ultra has never had that issue. So on that basis, I'd go for a new Ultra with the moot perks of the screen and 100% newness over an open-box Node 4.