It looks interesting. I actually wasn't even aware they were making a standalone Joker film until the trailer dropped, so it was a pleasant surprise. It looks like a refreshing breath of fresh air after 2 decades of all too similar superhero films, so I'm definitely interested to see how it turns out in the end.
As an aside, I know nothing about Joker's origins from the comics, so I will not be criticizing this film from a comics standpoint. From what I saw in the trailer, his origin story is not what I would expect, but makes sense given his character so I'm excited to see how it is portrayed in this film.