>>55019753USUM are in a weird spot where from a content standpoint they're superior to SM, but the story changes are minimal and backloaded, and all of them make things worse (though I do like Ultra Necrozma as a Pokemon final boss). So they're better, but they're not the definitive best gen 7 games like other third version style games.
There's also the problem that while I got into SM's story the first time, going through it a second time felt more tedious than anything and USUM did that just a year later. Gen 7 also has the highest density of cutscenes in a Pokemon game which doesn't help either.
All in all I like Gen 7 despite it having some issues (and me preferring gyms over trials), and from a visual standpoint it was a huge jump over 6 on the same system. It'll also likely be the last time that a Pokemon game was at all competitive from a graphical standpoint for the system it was on.