powe will probably be a very good role player on a good team in the nba. he has some talent and unbelievable determination. that is a good combo. he can score down low, and will probably develop a short range jump shot in time. he is a fierce rebounder.
but that is about it. his defense is ok, not great, but certainly good enough for playing against other bench players. passing? he is a black hole and rarely passes. but then, this may in part be due to doc. maybe doc tells him "rebound, score, dont worry about anything else right now." powe is not a very good ball handler either. plus, he does not jump high, so under the basket taller players (ala Z for cleveland) can block his shot.
davis, if he someday weighs less than most baby whales, has the potential to be starter on a number of nba teams. judging from his college days, he has range on his shot, even though it has not shown this year so far. he is quick and more coordinated than powe. he is definately strong, strong enough to make it almost impossible for other players to push him around. when he plants himself, no one else gets that spot.
i also think that davis is called for an incredible number of ticky tack fouls. that is partly because he is a rookie, and partly because he may anticipate the ball on defense and tries to make great defensive plays... but doesnt quite have the quickness/angle/etc down yet. a third reason is simply makes boneheaded plays, but he is smart enough to learn how to stop doing so.
while davis undersized ala powe, davis will probably have a better outside shot and more moves under the basket. so he will be harder to defend than powe someday.
powe is about what he always be...scoring with rebounds. which is pretty good.
davis has more basketball skills and i think smarts. powe is more valuable to the celtics right now, but davis will be the more complete player in a few years.
but for now, i am delighted that ainge has managed to get BOTH of them and their different skill sets on the celtics, and it only cost the team 2nd round picks.