Watched it yesterday and actually kind of liked it. I should preface that by saying that I went in with low expectations.
The bad is simply that its silly in parts, but also, you know, superhero film, so to be expected to some extent. Also, Fantastic 4 branding has always been a little bit more sickly sweet and wholesome than other Marvel properties, and it certainly does that.
However, its completely separate (at least for now) from the rest of the MCU, which is a good thing. The world has its own aesthetic which helps it to feel less like youre watching the same MCU film for the thirtieth or so time. It also doesnt do the somewhat overplayed were a dysfunctional team that will come together in the end dynamic and instead has the team functioning on both a practical and emotional level from the start, which is refreshing. They dont feel the need to have every member of the team doing something in every action sequence (which there arent actually too many of) just to make them seem relevant. And it doesnt do the classic Fantastic 4 thing of making Sue Storm the weak one just because shes a woman even though shes clearly overpowered as fuck.
Its not the best film ever or anything, and I dont think its going to course correct the MCU (especially because theyre going to merge it all for the next film anyway) but its okay and has things going for it and I totally expected it to be shit.
Id say apart from Guardians 3 and Far From Home, its the best post-endgame content theyve put out.