I've been a huge fan of the Story Mission since the original GOW, but never a big fan of the multi, even through I played it a fair amount on GOW II and III. This game not only doesn't compare, but even trying to play it as a separate game, not part of the series, makes it no better. The character controls are slow and non-responsive, the missions are terrible and you don't feel any sort of connection with the characters. Poorly written. I put this back in the mail the same day that I received it.
I am a huge fan of the GOW series. I own all 3 Gears of War and I was definitely interested when I heard about judgment. However, after playing Judgment, I didn't feel the same satisfaction and entertainment that I felt from playing the other Gears of War games. I admire that it tried to go a different route with the Declassified mission option and the flashback setting, but it just didn't have the same feel to it. It felt weird not playing as Marcus Fenix, and I think that change was something that should have been reconsidered. All in all, the game is definitely still worth playing, but I would strongly consider renting it before you purchase it.