I’ve used both,I borrowed a U1 for a couple of days locally to see if I would like their library vs Roon and also compare the overall sound quality to which is the most important aspect for me.I did like the ease of navigation with lumin but since I use Roon,HQ player and tidal,the lumin was good but I like the sound I currently get much better,much smoother and more of those analog qualities.
Offcourse my computer is highly tweaked and I’ve come to the realization that everything matters including the dc cables and connectors that I use with my pwr supplies.
Roon does imply that some big changes and improvements are in the works for 2018 but nobody has any info yet.
Best of luck to you,
Kenny.