8/10
I'm just gonna mention some thoughts I had about it below.
It feels impossible to talk about Midsommar without talking about Hereditary. I think that Midsommar is a simpler film with a simpler plot, but that doesn't make it worse. Midsommar feels like it was intentionally less ambitious than Hereditary which is fine because it delivers on its premise anyway. It borrows some horror tricks from it's "predecessor" which are still effective but aren't delivered in the same bone chilling way they were with Hereditary. There's also subtle comedy that's used well and doesn't disrupt the tone at any point. Like Aster's previous works, Midsommar is a slow burning build up to craziness that is really well delivered by the third act, and has some really disturbing scenes.
Overall, as per one of the film's themes, try and go into it with a completely open mind, don't expect Hereditary-level horror, and I think you'll really like it.