I love the Project Diva games but not everyone is into vocaloids so I guess I hesitate to recommend it to people unless they know what they're getting into.
If you're willing work your way through a lot of Japanese cutscenes (not all voiced, but at least the big plot stuff is), Valkyria Chronicles 3 is the best game in the series, in my opinion. It plays basically like 2 did, so at least that part shouldn't be too hard to figure out.
If you want something a little different, Idolmaster 2 (for PS3) is worth a look. No, really, at its core it's a fairly challenging management simulation game, though it also has rhythm game and visual novel components. Most of the game can be done without knowing much Japanese, though it's definitely an issue in the visual novel segments...
