In my night-time tests on a black-and-white chart, which I've been making for at least a decade now, several scopes have tied for the highest brightness rating of 8. The test is set up to remove objective size from the factors.
The 8's used to be limited to S&B, Leica, Swarovski and Zeiss, but in recent years Leupold VX-6's also qualified. I should also point out that not every Leica, Swarovski or Zeiss has rated an 8, just the top-end scopes. All S&B's have rated 8.
Might also mention that a scope's optical brightness is far from the only factor in the ability to aim in dim light. The reticle's perhaps more important.
