Pi with either an IQAudio or HiFiBerry HAT. Install and config is trivial unless you have never touched a computer before 
Sound is great.
Thanks Graham, Re the Pi, I assumed that installation and configuration would essentially be trivial. It appears I just need to learn more about the pieces and parts. I probably should search out some videos and dig deeper into the Pi world with any eye towards focusing on my very minimal Roon endpoint/DAC/
speaker audio needs.
If you buy a completely configured device, you only need to format and copy an image file to the micro sd card, pop it in, boot it and roon should see it. What type of output do you need (rca, optical)? Theres a version of all this that I think B&O are selling that includes an amp and is designed to work with conventional speakers ( http://gadgetynews.com/beocrate-bo-raspberry-pi-4-channel-amp-speaker-hack/ ). Its the most bang for the buck though and I wouldn’t be too intimidated by the build approach. Get good cases if you are going to build them yourself. They make great endpoints for roon.
@Louis_Casadonte, HIFiBerry have those. However they are expensive and the speakers seem to be commanding prices that seem insane to me on e.g. eBay.
Its the Hifiberry version that is a little less $. You can use this with any speaker.