I have owned one for almost two years now, which for DACs lasting in my system is like an eternity!
Mine replaced a Playback Designs MPD-3 DAC, which was excellent with DSD but less good with PCM files. I found the Bricasti to be a better sounding and more consistent performer along with providing a blacker background. When I purchased it the USB input 'upgrade' was already made standard, as well as the improved power supply and DSD64 support.
Once they added support for DSD128 along with some other upgrades I shipped mine back to Bricasti to get all of the latest changes. Their service is truly exceptional and Brian Zolner is a real pleasure to deal with. Bricasti is a truly first class operation that really stands out from much of the competition. He turned my unit around in
one business day, and the upgrade not only included firmware changes but a completely new DSP board along with the installation of OCC fuse bypasses. They have a history of only charging their customers their parts cost for upgrades which is more than reasonable.
I have read about other users who have said that the M1 DAC outperforms the latest version of the PS Audio DirectStream DAC, which has been getting many great reviews. The M1 DAC has been reviewed around the world since its release, to virtually all raves with most claiming that it is one of the best performing DACs available. Stereophile rates it in their A+ category for whatever that's worth. I believe that in order to better its performance you would have to spend at least twice the price or more.