I thought it was great. As a fan of the original tv series, I can say that Steve Carell nailed the role of Max Smart, and I was surprised. Unlike a lot of film adaptations of shows, this actually felt like an episode of the original. Not only did Carell obviously do his homework for the role, but he was funny in his normal, idiotic way, which isn't far from how Don Adams was. One thing I noticed and liked, was that the film didn't overuse any of Maxwell Smart's signature expressions, but used them just enough (such as: "I missed it by that much!" and "Ah, the old *insert any term* trick!"😉.
Also, I was really surprised that Peter Segal decided to have a make-out scene between Steve Carell and The Rock.