Being from Providence, I know a lot about Brooks. The guy is going to be a good scorer in the NBA for a long time. He's got a ton of athleticism, good size, great work ethic, and has shown in college that he can put up big numbers effectively. He tested as one of the best athletes in the entire draft at the combine, (7'1" wingspan, 38.5 vertical, Top 10 in every category but bench press).
As a Providence Friar, Brooks went from a 3 ppg freshman to a 24.6 ppg scorer to lead the Big East, albeit on a poor team. He showed steady improvement each season. He has a reputation as a guy who works very hard on his game and his fitness.
I saw him two weeks before the strike ended and Brooks looked to be a legit 6'6" (I didn't think he was as tall as his listed 6'5" and had him stand next to me and he's at least three inches taller).
Brooks is an NBA ready scorer and should get ample opportunity in NJ, which is one of the sorriest teams in the league. Considering that Avery Johnson started someone named Sundiata Gaines as SG tonight, (8 points on 9 shots), it shouldn't be long before Brooks is starting alongside the clinically depressed Deron Williams.
As a Brooks fan, I was bitterly disappointed when Ainge shipped him to NJ for JJJ and a future second round pick. I really liked the idea of Brooks as an understudy to Ray Allen for a season or two before starting at SG.
Brooks and JJJ are both very athletic, productive 4 year college players, and DA chose to go for big over small. That's certainly defensible in a league where height combined with skill is more of a commodity than scoring SGs. I just see Brooks as a prototypical SG and more of a sure thing than the beanpole-built JJJ.