James 1911,
I would not buy a Node 2i, it is several years old technology. If you are considering Bluesound (the interface is amazingly easy to use), look for the Node 130 at $599 (3rd gen) or the Node X at $799 (4th gen). You can improve the Node 130 with a linear power supply (LHY LPS kit $279), and it is a very good combo.
I have no experience with the Lumin, but will certainly be looking at their options when I upgrade my streaming setup. I do have a friend who is testing an Eversolo DMP-A6 which is getting good reviews, and a great price at $899