Okay, so full disclosure, I haven't used Netris at all yet, but I have used Sunshine/Moonlight extensively.

Moonlight is an app that's compatible with the Nvidia Gamestream protocol. You can stream directly from Geforce Experience to Moonlight, but Nvidia have deprecated it. Thankfully, an open source implementation of the Gamestream server exists called Sunshine, that is fully compatible with Moonlight (I don't know how much of this you already know but other people will read it too). However, due to limitations in the design by Nvidia, the Gamestream protocol is a 1:1 connection. You get the display out from your PC and Geforce/Sunshine handles launching the app. So if you want a single card to handle two different gamers at once, you have to split it and create VMs, then install Sunshine individually to each one. These resource partitions are often also static.

Netris on the other hand is based off of GeForce Now. Nvidia based it off of Gamestream, insofar as the connection between client device and server. But in terms of the software Nvidia runs on their servers, it's designed to handle dynamic scaling of hardware to accomodate multiple clients. It handles getting however many 720p or 1080p or 4K streams out of a specific card, and can often split them unevenly when needed. As well it handles syncing of cloud saves and the creation and destruction of VMs. So to me it seems Netris is the full package needed for sticking a 3080 in a server and having 4-5 users all be able to utilise the one card to game concurrently.

This will hopefully grow to become an excellent choice for smaller-time cloud providers to compete with Nvidia. And self-hosting it with a beefy CPU setup and SSD storage so it can handle multiple gamers at once. However, if you just want to stream a single PC for a single gamer (or even two seats using a VM running on your desktop) then Sunshine & Moonlight are going to be the better choice.