Spoiler free!
I thought it was great! I finished the show today and cried a little. I was happy with the pacing and ending, as well as the compelling characters and cool setting. It's interesting finding out about all the ghosts, as well as the main characters' relationship the whole season. I think the emotions and issues of characters were handled really well and pretty realistically. Mapplethorpe's attachment issues, Chester's stress and grief, and so much more.
I would consider this show, overall, for all ages. Nothing gruesome is shownโ It gives you insight on how each ghost died at the park, but it isn't violent or gorey. There's a couple curses, but mostly the language is clean. No sexual content. But I will say that some of the emotions, while handled really well, might be a bit intense for some people. I think that later in the show there are some implied thoughts of suicide as the series reaches its climax, whether that is acted upon or not is a spoiler, but no self harm is shown. I would consider this appropriate for tweens. My little sister (11) liked it and I (16) really loved it!
It's also a very accepting show, which I like. It has a few trans characters that are also dealt with realistically, which is cool. Not many TV shows have the bravery to address that stuff, or even show characters AS they're figuring themselves out. It's a breath of fresh air, a reminder that people like that aren't alone.