Most are good, some have issues, particularly square enix ports. Most are going to have some graphical compromises, but the majority run smoothly like Doom and Ys VIII. If you're interested in a specific game, look up a YouTube review that compares the switch version and you'll get a better idea.
Doom 1 and 2 ports actually aren't that good. You're much better off just buying them on Steam or GOG and playing the .wads through a sourceport.
-They have screwed up lighting in some sections
-They require a Bethesda account
-They are locked at 35fps, which does not divide evenly into the 60hz refresh rate of the consoles. So you get stutter.
-They don't render at the same resolution they output, so there are borders
-They used the low horizontal resolution rendering mode, meaning everything looks squished (twice as wide as it should be)
-All the Nazi stuff from the Wolfenstein secret leves was scrubbed out
-All the music runs at the wrong tempo
-They used the lowest sample rate possible for all sound effects
-There are major artifacts on the screen in split screen
-They left in the secret exits that take you to the 2 super secret exclusive levels from the Xbox ports, and the levels are in the games themselves still, but the secret exits don't work so you can't reach them.
-Doom II is missing No Rest for the Living
-Final Doom is not included
They're still playable enough but there's really no excuse for fucking up games that came out between 1993 and 1995 in 2019.
Unless the Switch is your only option or you just HAVE to have them on a portable, don't buy them. Same problems apply to the PS4/XB1 ports.
They're significantly worse than the X360 and PS3 ports, which themselves have many of the same problems listed above.
