I just binged watched Star vs. this past week with my SO and I think it's... ok?
I'm not a huge fan of the character design, yeah sure it's supposed to be all bright and sparkly but I think characters' facial features are drawn way too exaggerated, nitpicky I know but it kinda puts me off. Some of the humor surprised me by being pretty raunchy and gross out, there was times I was forgetting it's a Disney cartoon and not a CN one. For a show that seems to pride itself on lolrandum shenanigans the episodes that go really serious and are then never brought up and have any impact ever stick out like a sore thumb (staring hard at the episode of Marco becoming a transdimentional badass adult in a teenagers body).
However I'm genuinely surprised that the characters don't annoy me, particularly Star herself who I thought I was gonna completely despise with all the lolrandum. I'm also thankful that Marco's ethnicity isn't too distastefully shoehorned for representation points (I'm Mexican myself) and is just a character that just so happens to be Mexican rather than a Mexican character.