I never felt Quinto's Spock was off, at all. My impression is that new Spock's childhood was somewhat different from Spock Prime's- his father was more supportive and did not cut him off. In the book, during the discussion after Spock whups up on the bully, Sarek puts his arm around his son. After telling the VSAcademy thank, but no thanks, Spock sees respect in his father's eyes.
This made him more confident, or perhaps more at peace with himself. He allows himself to have a relationship with Uhura. He seems comfortable as the only Vulcan (I saw) on the Enterprise working with human. So, I see him as simply reacting a bit differently, given a different past.