I voted "bad." There were funny parts, but it doesn't compare to "Borat."
The difference is that Borat is a sympathetic character while Brüno isn't. A cheerful foreign guy who turns out to be cringe-worthy is hysterical. You want to like Borat, but he's awful. Brüno is a bit mean-spirited and never quite wins the audience over. They also went heavily for the gross out factor, misjudging the audience. While Brüno pushes the boundaries of film, it doesn't come anywhere close to pushing the boundaries of the Internet. No need to name particular shock sites, but the younger audience is pretty darn near unshockable in 2009. Instead, the film should have make Brüno more likeable and focused on that awkwardness, like in the hunter scene. That long moment of uncomfortable silence was the funniest part of the movie. If they had found similar scenes, then it could have been as much of a classic as "Borat" is.