-in addition the previously mentioned: settings/*processing (or lack thereof) and with regard to input; pixel density vs. panel size,
..there is also:
back-lighting effects (which can be better or worse for any given TV or Monitor), and particularly in conjunction with that:
glass thickness/parallax (with potential light-bleed from the back-lighting), and quite likely reflective effects from the room and TV frame onto the glass. In this respect there is also the glass finish, which is often "matt" on a monitor and seldom so on TV's.
A couple of years ago I purchased a 42" 4k Hisense TV for my fathers system, the pixel vs. panel size is IMO good (not great) and if you look close you can see it but it really isn't what I'd consider a problem, instead the problem is the amount of light hitting the glass panel and also the small frame of the TV that (though not much) - still reflects light back onto and into the glass, which is still considerably thicker than the 24" 1080P monitor he uses for browsing. Of course it's largely panel-dependent: there are some really excellent panels out their that are just about as good as decent LCD monitors in this respect. (..ex. Sony is usually pretty good about this.)
*"processing" ALSO includes text on the Windows 10 side of things (not just the TV). The result of text scaling in 4k with Windows 10 doesn't produce a particularly good result when enlarging it, particularly text with something like Desktop icons:https://www.tekrevue.com/tip/windows-10 ... y-scaling/