Who portrays the better Spock - Zachary Quinto or Ethan Peck?

Comparing Quinto and Peck's Spock portrayals

As a series in comparison to movies, - in “New Worlds" Beck certainly had much more to work with than Quinto, given a 2-season series and now a third in the works. However, Beck's portrayal of Spock is grounded in family and personal growth over Starfleet's achievements and logic. This is not to say that Beck’s Spock was more adept at managing emotion and logic than Quinto’s Spock, however, his portrayal seems to balance them equally.

I will say that in comparison, Quinto's Spock coming out of Starfleet Academy is a younger version of Spock than Beck’s. Beck is a more seasoned officer and much more in control of his struggle with emotions and logic than Quinto. Peck gives a more calm, centered, and self-assured version of Spock, where Quinto is often at odds with his emotions. For example, at one point when Kirk was dying in "Into Darkness," Quinto screamed “Khaaaaaan” with a high degree of rage and emotion that his friend was dying. Quinto’s Spock was then focused on killing Khan, whereas a more logically portrayed Spock by Beck, may have worked out a tactical strategy to stop Khan versus an emotionally driven plan to kill him.

Beck’s portrayal of Spock is controlled with less about the highs and lows, going from non-Vulcan-like emotional outbursts to caustic logical clarity of thought. In “New Worlds" I found Beck's on-again off-again romantic triangle between his arranged fiancé T'Pring and the ship's medical officer Dr. M'benga "fascinating"! Beck was brilliant in his balanced portrayal of the Vulcan tradition of arranged marriages based on what's logically best for a couple versus his clear emotional connection to Dr. M'benga.

Is an analysis of Quinto and Peck illogical?

In the final analysis, both Quinto and Peck are extremely talented actors with different sets of Star Trek canon act against them. Quinto's portrayal of Spock is set in a larger-than-life action-adventure genre of the Star Trek movie lore. As such his portrayal of Spock is delivered in an action-driven faster-paced plot that has to be solved within 2 hours versus over the course of a TV series.

On the other hand, Peck’s portrayal of Spock spans across multiple seasons of a TV series "Strange New Worlds" that can be delivered much more slowly. Given the foundation of Star Trek canon and storytelling in a TV series, Beck has the advantage of growing into Spock. Peck has the opportunity to show all the nuances and subtleties of a biracial Vulcan/Human navigating his way through the traditions of Vulcan culture, the regulations of Starfleet, and his need for acceptance and achievement. Acceptance Peck so desperately wants, despite how often Vulcan cultural tradition may conflict with individual needs and desires.