In the past, medium format digital was characterized by
- better s/n than APS-C/FF (bigger sensels, even with more pixels)
- better resolution (greater number of pixels) than APS-C/FF
I cannot say that 'better color' was a characteristic, as both formats are inherently limited ultimately to the same 8-bit color spaces! Maybe it might be said that 'better gradation of colors' occurs with medium format since more pixels capture the same amount of subject area, in this way it is analogous to film benefits of old.
But FF digital has long rivaled the quality of medium format, it was not as easy a 'walk away from 135' in the days of film.
A discussion on this very topic: would an image produced by a 50-megapixel sensor be expected to have the same quality no matter the size of the sensor itself that produced it? https://www.dpreview.com/forums/thread/4023838
...but does the image really LOOK any different?! I recently engaged in a discussion on a film forum about differences of 'appearance' of 135 film vs. 4x5 film.
In short, you can get IDENTICAL field of view and DOF and even identical magnitude of far field blur, so the only apparent difference is the tonality of more grains per subject area and the decrease in apparent size of film grain due to lower magnification for same print size... IOW, 'NO' there is not an apparent difference other than tonaity gradations or grain size.
Now having said that, I can tell you that in the days of film during workshops showing shots projected on a 4' x 4' screen, after viewing 135 slides there were notable gasps in reaction to shots projected to same size but captured on medium format! Whether the same effect would be noticed in digital sensors is an unknown...digital projectors are so incredibly DEFICIENT, at best they are 2K or 4K in resolution, compared to 20MPixel or 50MPixel sensors! So the projection is the lowest common denominator in such comparisons.
Would you SEE a difference in 50Mpixel FF vs. 50Mpixel medium format?...dunno!
Yes, larger format can have shallower DOF than smaller format, but when DOF is shot to be the same with both, will you see a 'more striking look' in the medium format shot?...dunno!
In theory, since medium format is enlarged less to make the same print, medium format lenses MIGHT deliver more line-pairs per millimeter of print...but then again in the last decade there has been a lot of new FF lenses with better resolution, while medium format lens design has not bewen so progressive in advances in results (due to smaller market demand)...so they might NOT today have a margin of performance any longer, compared to differences visible in 1990 FF lens vs. 1990 lens medium format.