These are actually good games. USUM too (but not worth buying if you played SM.) we all know they have glaring issues, but this makes their cool parts extremely underrated.
>not a huge amount of new mons, didn't pad dex with shitmons
>enjoyable characters (Guzma, Team Skull, Aether Foundation) outweigh shit ones (Hau, Ultra Recon Squad)
>Ultra beasts are some of the coolest additions and actually are each given their own unique character; portrayed to be freaky, bizarre, otherworldly monsters, which fits their designs perfectly (which are based off of invasive species)
>Ultra Megaopolis, despite being a glorified hallway, has a cool fucking atmosphere/aesthetic.
>Ultra worlds are incredibly unique and also have great aesthetics/world building just by design alone -- a simple textbox saying you're X amount of light years away is all you need to cement the feeling of being isolated in a strange place. That you're so far away, nobody can help you. (Except Pheromosa's world, Ultra Desert, which lets you call ride Pokemon and stupidly completely destroys the illusion)
>Aether Foundation is closer to a secret government organization than an evil team, which is cool, but the execution kind of sucked
>Team Skull isn't tryhard bullshit

Mainly it's the endgame/ultra space parts that I think salvage these games. Maybe it's because I just really like that sort of thing, but I think they were very well done, and the best content since gen 4.