Not Horrible At All
The film is great fun, and well made. Each of the actors — the aforementioned leads as well as their bosses, played by Kevin Spacey (worse here than in Swimming with Sharks), Colin Farrell (in an absurd but hysterical comb-over), and Jennifer Aniston (eat your heart out, Angelina Jolie), plus Jamie Foxx, as the guys' "murder consultant" — turns in a solid performance, and the script by John Francis Daley, Jonathan Goldstein, and Michael Markowitz has a bunch of quotable lines (including a Good Will Hunting reference that I am not going to include here). I even love how in one scene, a Muzak version of the Gnarls Barkley song "Crazy" plays in the background. Nice touch.
After a smart, well plotted first half, the film does start to sag a little about two-thirds of the way in, but it pulls itself together in the end to leave you smiling. That is, if your mind isn't racing with ideas. I'm giving Horrible Bosses a B+.