Of the 3 choices (Scout, Rivals, & BDJ), I would say Scout is the runaway winner.
Scout:
I know that site gets bashed around here (with good reason) and people still call him Rosebowl, but Steve does an excellent job following recruiting. His "Bones" are the first thing I check when I get up in the morning. The "Bones" are recruiting tidbids that he gives in his nightly chat. They are then posted in the recruiting forum to be reviewed. Read these daily, and you'll have no problem keeping up with those "in the know" people about recruiting. Steve is also considered one of the Scout's networks best football evaluators. If he says a kid can play, then the kid can play. No Yancy BS here.
Also as a baseball fan, Gene has been doing a solid job following recruiting. He has posted more baseball recruiting articles in the past 9 months than I've ever seen combined on the other sites.
BDJ:
As Dawg in a pile alluded to, their recruiting database is pathetic. It's not national, it not updated regularly, it has many mistakes, it's just pathetic. Their articles are fine, but you can get basically the same articles from Scout along with a national database.
Rivals:
Nationally, they are considered the better network, but the MSU site hasn't been worth visiting since Rob left. They currently don't even have a recruiting forum.