Let me also say I was an early supporter of Margot Robbie being cast as Beautia in the upcoming Captain Marvel movie. She was on my short list of top 2 or 3 choices. When it was announced she was cast as Harley Quinn instead, my reaction was, "Really? We need this?"
So, after watching Suicide Squad my overall impression is that Margot Robbie was the highlight of the movie and she made me a Harley Quinn fan (or more accurately, a "Margot Robbie as Harley Quinn" fan). Her scenes are the most interesting of the film, and when she is on screen, no matter who the focus of the scene is, she commands the viewer's attention. The bad part is, Margot Robbie is not the star of this movie.
The script is very straightforward, unlike Batman v Superman, where the first two reels we are introduced to the characters with some background flashbacks (including cameos by The Batman and The Flash, and for the true Harley fan, her original animated costume), while setting up the motivation for creating Task Force X. Carla Delevingne's June Moon/Enchantress goes rogue and the Suicide Squad have to bring her down. There is a dominate soundtrack to the film, which didn't really bother me. In fact, without it, I think the film would have dragged in spots. David Ayer's directing brought the right balance of humor, which Zack Snyder's efforts lack, and a full color pallet, again unlike Snyder's muted colors. Overall somewhat better than Batman v Superman in certain ways, but not nearly as epic.
And then there's Jared Leto's Joker. All the promotion and trailers for the movie mislead us into thinking the Joker will be a major force in this movie. Not quite. It's little more than a glorified cameo. He gets just slightly more screen time than Batman, which is odd considering Leto gets second billing in the credits. Perhaps Leto's best scene is where a gangster kisses the Joker's ring, and Joker's response. According to new reports, the majority of Leto's scenes were left on the cutting room floor. I know of at least one scene I saw BTS clips of where Joker is confronting Dr Quinzel on a street, at one point putting a gun to his own head, when a trucker enters the scene and Harleen grabs the gun from Joker's hand and kills the trucker. It's not in the final cut. Because of this, I really can't judge Leto's performance as the Joker. The things that really stood out to me was his physical appearance- a cross between Billy Idol and David Bowie in a pimp's wardrobe, with punk rock green hair, heavy metal tattoos, and a rapper's grill. The other thing is that the Joker comes off as a love sick puppy chasing after Harley, while Harley is the dominate member of the coupling--essentially the opposite of the original dynamic from Batman The Animated Series. Another odd thing is that it seemed Harley has more chemistry with Deadshot than with the Joker.