If you're conservative, take Duckett. He's big enough to punch it through the goaline, Dunn isn't. Plus, the arrival of O-line coach Alex Gibbs is going to open things up immensely for the running game. Duckett will be much more productive and consistent this season.
For the risk-taker, you might be willing to gamble on the "higher reward" in Green. If you'd rather have an explosive game here and there over steady production, Green's your man. He can rip off the big plays and probably is the greater talent between the two.........but oh those "ifs". If his head is on straight like he says it is.......If he's healthy, focused, and ready to play........If Lee Suggs will just roll over and let him regain the starting role. That's a lot of ifs.
Personally, I'd take Duckett over Green by about 5-6 rounds.