I use and can recommend the Auralic Aries G1, a little more costly than the Lumin and a wonderful-sounding unit. To my ears, it was a big step up from my original Aries femto. I have not compared the U1 Mini to the Aries G1. I suggest that before committing to either Lumin or Auralic, you have at-home auditions. Auralic will allow that; I hope that Lumin dealers will, too.
One advantage of the Auralic is its DSP engine, which can apply up to 20 bands of PEQ if you want. It could be useful to kill bass peaks. To my ears, it’s remarkably transparent.
Lumin’s software is well liked, but any decent streamer should be compatible with standard OpenHome or DLNA control points, so you can pick whatever software you like. IMO often third-party software is better.
BluSound has its own software ecosystem, reportedly quite good, but incompatible with OpenHome and DLNA.