A few observations with the Windows version:
7700K and 1080Ti (on an HDR TV that doesn't display HDR right)
Picture quality in Foundation TV series (HDR source) is excellent - as good as MadVR, and maybe better. This is compared to MadVR tone mapping. However, it stutters occasionally where MadVR drops zero frames.
Ryzen 7 Pro 4750G using integrated APU video on an HDR capable screen:
Tested with Allegiant UHD HDR rip:
Looks over saturated and is juddery in places in JRVR.
Small improvements in PQ with hardware acceleration turned off, but still over saturated), but less-so than with acceleration on.
MadVR, is smoother and looks better with both HDR passthrough and tone-mapping.
With an Adele (1080p SDR, 25fps converted to 29fps, I believe) concert bluray JRVR was better out of the box. I had automatic display refresh rate set to show 29 fps material at 29 Hz. In MadVR it is stuttery, unless this setting is changed to 59 Hz. JRVR did a good job even at 29Hz compared to MadVR.
It's still very exciting to have thins feature, even as a preview. I can't wait to see it in its finished form with HDR pass-through and improved tone-mapping, some configurables and an OSD for monitoring/debugging.