>>93492576I think the voice acting is pretty great but I also wasn't impressed at first.
Star can sound sort of fake at times in the early episodes when they tried a bit too hard to make her always wacky and funny. Once the writing gets stronger and the action slows down a bit later in the first season, they show more of her emotions and her VA gets the chance to show more of her range. The voice also works better when more of her personality is shown and it's clear she's not just supposed to be one trait, ex. crazy/cute/etc. Though if you don't like the pitch that's just how it's gonna stay; it's actually supposedly higher than Eden Sher's normal voice and yet is constantly called too low (I think it works for establishing her as a teenager despite the cutesy art style).
Ludo's voice gets noticeably a lot lower and less screechy by late season 1/all of season 2. Think he's maybe the one character where the difference in voice is immediately recognizable between episodes.
Some side characters do have pretty shit voices (Alfonzo, Brittney, some of the monsters) but pretty much all of them stop consistently appearing within season 1. I think Pony Head sounds fine but if you think she's a bitch then she's gonna grate too, but she also doesn't show up very frequently.
Other than that not sure which characters might be bothering you, but for most of the ones some people complain about at first it's an "it gets better" situation. Marco sounds pretty much like a standard young teenage guy in a cartoon to me.