I think this will be a good trade for the Nets in the long run. Yi has a lot of upside, while Jefferson is pretty capped on his growth, plus he has a max contract, but is not a max type player IMO. Yi, Bowie, Sean Williams and Krystic (if healthy) can develop into a very good front court, and when LBJ becomes a FA, the Brooklyn Nets will be in a great position. Don't forget they have Devon Harris now, who is going to get better, and would be a good back-court mate wtih LBJ.
I am also relieved that NJ traded RJ to Milwaukee, and did not trade him to the Lakers for Odom, which had been rumored. The Lakers would have matched up alot better with us had that trade gone down.