It's not official (and he can't "report" until next thursday, for some odd reason/rule), but Charles Johnson is in, and he confirms it. 6 years, $70+ million - it's been reported as 70, 72, 76 million in various articles. $30 million guaranteed seems to be the constant statement, and a hefty one.
Carolina made the heaviest push, not only offering more, but also bringing GM Marty Hurney (and some outlets suggested Rivera and/or position coaches) to Miami, where Johnson was stationed.**
Johnson himself said that family pushed the Georgia native (and Bulldog alum) to sign with Atlanta, and apparently Denver made a hard push. Carolina made it happen, however. Johnson suggests that deal was the best; he probably could've sounded more loyal about it on twitter, but he stays, and that's what's important; he also mentioned being interested in still facing Atlanta twice after what he feels was a snub in what they offered.
**Hurney also visited potential head coaches in the offseason by going to them instead of bringing them in. I wonder what that's about, but it seems to be paying dividends.