I made further investigations in the case of the MIST's different video outputs.
I used now the Amiga AGA (minimig) latest core modded by Sorgelig (YPbPr out).
Used the same methods during the test as decribed in the post below:viewtopic.php?f=101&t=31006&start=25#p310037
As I see, the brightest and sharpest picture is over native VGA.
The second place is a 'dead heat', scandoubled component and scandoubler disabled SCART gives the same sharpness, but the YPbPr is brighter, therefore a little bit better.
The scandoubler disabled component output results the most blurred video.
That was a surprise to me, I thought the component input's quality is much superior compared to SCART connector. Perhaps the problem is in my TV set, or the advantage depends on the difficulty of adaptor: the VGA2SCART cable doesn't contain any active electronic part, unlike the VGA2YPbPr converter, which contains transistor, capacitor
and resistors too.
I found further interesting phenomenon: in High Res Laced mode, if scandoubler is enabled, the picture is flickering, in this case the framebuffer's content is blocky. It works inversely as expected: disabling the scandoubler the picture does not flicker anymore.