I'd take Westbrook over Griffin, Irving, Davis..there isn't a young guy I'd trade him for straight uP in the league probably, aside from.Lebron or Durant.
*Taking off GM hat*.
I would take Irving over Westbrook at this point. I'd probably take Westbrook over Griffin, although it's close. I have no idea what to think of Davis.
To defend this position:
Right now, at age 19, Irving scores 2 points less per 36 minutes than Westbrook. He rebounds at about the same rate, and averages more assists per minute. He is significantly more efficient, and he seems to have better instincts than Westbrook.
Irving's rookie year was much better than Westbrook's, and it's fair to assume that he will continue to improve. In a year or two, Irving could very well be a top ten player.