Dammit, I went into this movie hopeful after the positive reviews, but it was an absolute chore to watch. I think the problem is that it was produced to order from too many incompatible parts. You can do a movie about a gritty GCPD cop who has to work with criminals to get the job done because of her sexist buddies, but she can't exist in a world where Harley Quinn can wander around supermarkets without anyone noticing
[1]. You can do a movie about Harley Quinn's Very Bad, No-Good Day, but you can't keep pulling attention from her to set up four other protagonists and two antagonists. You can say that Harley is a mean baddie, but she's going to look pretty lame just hitting people with baseball bats when Huntress is shooting them in the throats with a fucking crossbow.
There's the makings here for two decent films: Harley Quinn trying to survive when the whole city is bearing down on her
[2], and Birds of Prey vs Black Mask (with, perhaps, Montoya in the B-plot, tracking down Huntress). But putting them all together, adding in the sub-Deadpool meta commentary from Harley and using a convoluted nonlinear structure that adds nothing to the story has left this film overstuffed mess.
[3]The only saving graces are a handful of arresting shots, some really excellent fight scenes
[4] and a roundly excellent cast
[5]. Robbie does great on all fronts, as expected, but Mary Elizabeth Winstead really makes a mark as Huntress despite only getting about ten lines of dialogue. I would really have liked to see her given more time to breathe, and hope she has an opportunity to return to the role even if the chances of a sequel right now look very slim.