Great seeing my video linked here
My background is more Commodore, so I can only speak about C64 and Amiga demos. At first I was very impressed with the Mist. But the more I use it and try other things, the more compatibility issues, glitches appear, which is a shame.
The C64 core is quite poor IMO. I tried maybe 3 demos, and all of them have visual glitches, one crashes. I couldn't get Lotus Challenge to run either. All of these work fine on the emulator (C64 forever).
The Amiga core AGA and non-AGA seem much more refined. But there are still some glitches. In the Desert Dreams demo it seems that 3D rendering runs too fast. A friend told me it feels like it's run on an A1200. So in some animations the 3D rendering pulls ahead of the movie script. Can be seen in the Melon going past the pyramid and the rockets exploding past the ship. There is also a vertical line on the left side during the dot demo.
Again, Amiga Forever emulator displays this correctly.
So yea, my initial excitement has faded somewhat. It's a great machine, but the compatibility issues are bit disappointing.
Interesting comment about the input lag. Does this get better with faster machines? And how could one test this beyond a subjective feeling. Maybe using a camera?