BS Node 2i: WiFi or Ethernet..?

I have. Easy to do.

I’ve used my Bluesound Node 2i with both wifi and connected via ethernet and I’m hard pressed to notice much of any difference in quality.

My internet setup is the last generation Netscape Orbi and I compared by running ethernet from one of the satellites vs connecting via wifi which can come from satellites or the router depending on network traffic

Also, I'll echo what was said above - the biggest upgrade to the Node 2i was the power cable; 
I found my favorites to be a $10 Hosa cable from Amazon US to the $240 Acoustic Revive Absolute Power from Amazon Japan. Ultimately, I preferred the Acoustic Revive but the Hosa is better than some much more expensive cables I tried.

Ethernet wired connection will ALWAYS be better. It will always provide a more reliable medium.

If wifi works perfectly, there will be no difference. However, since wifi is almost always prone to distance and/or interference and connectivity issues, it will always be inferior to ethernet wired connectivity.

Honestly not sure whether or not Ethernet beats WiFi. I have a node 2 I only use for radio stations now and it’s hard wired. However, I don’t think there’s any way using a wireless access point could possibly be better than just using the wireless option on the Node. That is, you are still using WiFi  either way. If true Ethernet is better than WiFi you won’t realize it using a wireless access point. 
For what it’s worth. 
Matt