Here is how I see these two. Both are strong perimeter defenders, although James is probably a bit better. Lighty is the far better shooter. James is a far better rebounder.
I think I'd like to see James succeed, partially because as a former top draft pick for us, I'd like for him to overcome his foot injuries and make good on his abilities with us. #Loyalty. The other reason is he is a very close friend of Kevin Durant's. It won't hurt the longer term plans for 2016 to have him in the fold.
I do think Lighty is the better fit, and if he can keep improving defensively, I think he can play a Bruce Bowen role in the NBA. But if we land Korver, James might fit a better need as he's the more athletic of the two. Either way, these are two great prospect for the Nets 15th man.