Looking for best streamer without DAC under $3500

+1 rbstehno

For under $3.5k?  Easy, just get Node 2i for $500 and enjoy the $3k you save. Seriously. You need good user interface and functionality, such as ability to integrate with streaming services, external disk, user interface to play your selections. Like @rbstehno said, this is just a specialized computer. $3.5 is more than you'd pay for the newest full-featured MacBook Pro!

I’d look hard at a used Aurender ACS10 which has a built in ripper and sounds great. Excellent build and the operating program is great. It’s an elegant solution if it fits your bill but it will need to be used to be near budget. 

My Lumin U1 mini works exceptionally well with my Chord Qutest as a Roon endpoint streaming Qobuz or local files from my MacBook or Qobuz or local files from my iPhone Lumin App...  It just always works...

$4k for a computer? The only reason why somebody would do this IMO is because they are stuck using usb and they need to get the best performance possible out of a flawed interface. SSD for music, also overkill. Again, the only reason for using ssd is because you need to place a server in your audio room and you need to have the system as quiet as possible. Save the $4k, get a 5-8 year old Mac with an internal 500GB ssd to run roon, get a good couple of TB drives to store music on and for backup (or create your own raid 1), and place in t anywhere in your house except the audio room. Then go get a great dac That has an Ethernet connection and you will be in good shape.
If you buy any proprietary server, who is going to support this? If you buy an Apple, thousands of Apple geniuses in person or on the phone can help. If you buy a proprietary server which probably runs some kind of Linux OS, how are you going to backup the attached disks, and worse, how are you going to restore your ripped data if a disk crashes (ssd or hdd disk will crash).
There are quite a few people that promote this on different sites

If you can find one, a used Innous Zenith MKII would work just fine, and it can host Roon Core.