I absolutely love Lego Rock Band and my wife is more excited to play a Rock Band game than ever before. While I'm not nearly as mad about the content filter as some people are, I do think it is the biggest problem with the game.
My wish is that the content filter had been an in game option with some kind of parental control. The Lego Music store wouldn't even have to show the songs, but at least give you the ability to pull in what you want. I still have a lot of songs to play, but it's just so surprising that only about 50% of the songs I have pull in.
Anyway, it could've been done a little better and avoided all the complaints, but regardless the game is awesome, super fun, and will have a lot of play time from me.