I really liked about 50-60% of this, but the rest dragged. The action scenes are, to my taste, probably the best of any comic book movie from the last 10 years, and I do enjoy Robbie as Harley Quinn, and liked some of the quirky touches (particularly the opening animation) and McGregor hamming it up in a way I assumed was now illegal. But the exposition/flashback heavy narrative drags, and Perez and Smollett-Bell's characters are mostly dull here and take up way too much time for what they bring. Mary Elizabeth-Winstead's side character is kind of fun but suspicions rise that they're introducing her mainly for spin-off or sequel material, and of course at the end it becomes clear it's all pretty much a set-up for a potentially much more interesting film which now will probably never be made.
To end on a positive note though; OK I admit it, I'm the one who liked the title.