I just saw it. Overall, I thought the plot was a mess, the pacing was bad but other than that, I genuinely enjoyed it. It's not a great movie, and I'm not gonna shit on people for disliking it, but personally I liked it a lot.
The positives are pretty much all character related. I liked near everyone. I'm surprised how much I ended up liking a near nobody like El Diablo, and I had to laugh at how the editing of the movie makes Slipknot have like not even ten minutes in the film. Harley was awesome, and Deadshot was great and Will Smith did a good job.
Amanda Waller was the best character, she was awesome start to finish. When she shot all the people in that room, I thought 'yep, that's Waller'. She'll do the right thing in all the wrong ways. Batman's cameos were great, loved Waller implying she knows just what he does. Liked the brief Robin mention in Harley's introduction screen.
Joker was...eh. The way some people complaining over his lack of screen-time I thought he'd have like three minutes worth but he was in it more than I expected. Still not a lot and boy a lot of stuff from the trailers is gone. Can't fault Leto for supposedly being pissed over it. But he brought my main issue with the movie.
My biggest fear of the movie was that they'd turn the Joker/Harley relationship into the opposite of what it was. And they did. The Joker is pretty much just straight-up in love with her and does nothing to be a dickhead. He manipulates her which is good, solid with the usual origin but then he's all 'oh great I really care about her' when he presumably got her to jump into the vat just to get her killed. I heard they cut a scene where he hits her and man, that should have been in the film. That kills the character more than the whole gangster stuff.
Once again, movie's plot and pacing is a mess but I liked the characters enough to enjoy it.