Music industry bible Billboard Magazine has posted a review of "4 Minutes":

It doesn't take anywhere close to "4 Minutes" to realize that Madonna is poised to score her first top 10 hit since 2005's "Hung Up." The launch single from upcoming "Hard Candy"—her 11th and final studio album for Warner Bros.—co-stars Justin Timberlake, with production props from Timbaland. There's an awful lot going on in the busy dance track: sing-song verses, insistent foghorns, cowbells, chants of "tick-tock" and "Madonna, Madonna," and a rap from Timbaland—but the trade-off chorus between Madge and Justin of "We've only got four minutes to save the world" is hooky enough unto itself to sell the song. "4" qualifies as an event record between superpowers who not only share equal billing, but sound gangbusters together. Expect instantaneous penetration for this spring break '08 anthem.

Source: Chuck Taylor, Billboard