As the New York Times writes in summary its review of Barclays Center is "Two Brooklyn architecture reviews in one: a rave for the Barclays Center arena, a pan for the larger development, and a plea to make the development worthy of the arena."
We'll focus on the first part: the arena and happily quote critic Michael Kimmelman's coupe de gras on Barclays Center...
What’s clear now is that Barclays makes the Garden the second-best arena in town, which is to say even worse than we already thought it was. On the up side, losing face and business to Brooklyn may nudge the Garden’s competitive owners to reconsider moving in the coming years to a new site and a better home, which would finally make it possible to fix Penn Station.
The build-up to that line is filled with praise for the arena, outside and in. "The black-box vibe, with its gray-and-eggplant palette and terrazzo concourse, distinguishes it from Madison Square Garden, exuding a sophisticated chill, warmed by an eager, Disney-trained staff." He also notes of the canopy and oculus: "Rusted panels jutting suddenly like a solar flare to create an open-roof canopy, a giant loop cantilevered 85 exciting feet from the arena wall. The inside of the loop becomes an electric billboard, underneath which the main entrance gives views from the street through the lofted lobby..."
Kimmelman has his quibbles about the arena and questions about how it all fits together with the urban fabric of Brooklyn and whether when the rest of Atlantic Yards is done its glory will be subsumed amidst towers with less architectural flair. But now like most critics, he likes it a lot.
An Arena as Tough as Brooklyn. But Street Smart? - Michael Kimmelman - New York Times