Well-acted, interesting drama / thriller from Steven Soderbergh. This is a flick that definitely benefited by knowing next to nothing about the plot, and if you haven't seen it, this is your recommendation. Read nothing further and just check it out.
Minor spoilers ahead.
I loved the shift in protagonist throughout the movie, and the morphing of the kind of movie you're watching. It's not as schizophrenic as something like From Dusk Till Dawn, but it was well done and made for a compelling watch. Underneath everything is also a message about pharmaceutical companies and the relations they have with doctors. It's delivered perfectly- the point gets across without it being beaten over our heads as viewers.
A minor complaint: I'm not crazy about the color palette and cinematography Soderbergh uses, and it's amped up to 11 here. He seems to be going to the blown-out colors and fuzzy look of 70s film to an extreme now. At the very least I suppose it is a distinct visual style.
Palette aside, I found Side Effects to be an extreme pleasant surprise. Soderbergh hasn't been putting out a ton that I've been interested in even checking out lately. The last that seemed to fit the bill was Haywire, and I found that to be a disappointment. Not so with Side Effects- an entertaining, somewhat thought-provoking, and satisfying watch.