Well the Nuggets are never going to get equal value for Melo, or anything close. That said, if this went down, I'd applaud Ujiri. Not a bad package.
If anything, Denver could get the last laugh here, considering how Melo's made them his prison bitch through all this. Billups, Rip, Melo, and Brook Lopez isn't going to win the Nets a title. They'd be lucky to get 1st round home court with that team, in a full year of play, let alone this season. They'd also be emptying just about all their tradeable pieces in this deal, limiting how much improving they can do until Rip and Billups are expiring contracts (and even then, you need actual prospects to go with those contracts, unless some other team is in a world of financial hurt and has something desirable).
Meanwhile, in Denver, Favors has very high upside and could develop into a franchise player at PF. His lame stats so far are largely due to lack of minutes and Avery just horribly misusing him. Harris is a nice player who could easily be flipped elsewhere for something more useful to Denver (Batum?). Worst case scenario, you have a proven scorer next to Lawson. Morrow's nice. Unloading Billups is huge (unloading Harrington would be better, but doubt that happens).
Keep your chin up RSFFL, this could end up like the Jason Kidd deal did for Dallas.