I can comment on Lumin X1 compared to PS Audio DSD, but I used my DirectStream DAC with microRENDU, not Lumin U1. I initially ran DirectStream with USB, but later on added the Matrix X-SPDIF 2 and used I2S from from the Matrix to the DirectStream. I still have all of that but not actively using. The DS has always been a very reliable unit for me, but I prefer the Lumin X1 for both sound quality and simplicity. The X1 is a network streamer DAC and must be connnected to the network to function. Upstream of these I used a SMG SonicTransporter i5, which worked well for all. I will be making a change there soon.
In my experience, the X1 has better imaging and soundstage plus dynamics have been superior for me. Be advised that the X1 needs considerable burn-in time for best sound presentation. I had read 400 hours, and believe that is a good projection. I noticed much improvement after 100 hours and kept improving. Lumin now offers an accessory remote control, which I have and like, but does not eliminate my use of iPad or iPhone when I am setting up/changing settings for the X1 and/or using the Lumin App for music control and selection. I also have Roon, which does not require the use of the App, other than turning Roon Ready On or Off for the X1.
I highly recommend the X1.