Davy is so much more talented than Ferrer, but Ferrer has a much better mental game.
What makes you say Ferrer has a better mental game? Davydenko has a history of being erratic on the big stage, some very good victories (his amazing record in finals) with some disappointing defeats (losing in three to Federer, RG 2007 comes to mind). Ferrer has been able to have mental domination over the weaker players but he has also lost big opportunities (against Nadal this year for example). IMO, Davydenko just plays an extremely inconsistent game, when he goes off the boil, he can lose to a lot of players. When he plays well though, he has usually been able to carry that form through to get victories.