I've never held a Nikon HG 10x42, but I have the 8x30, and I'd be surprised if the Nikon was right up there with the Maven for brightness or surpassed them in sharpness, contrast or speed of focus. I don't know about CA.But you are given up a lot of FOV and putting up with more CA.
As for FOV, the Nikon are at 360, which is the same as the Maven B1.2 and not a huge difference from the B6 at 340 (and BTW, I'm not aware of any 10x50 that has a much larger FOV than that, although who knows if Swarovski or Zeiss have a new generation of ultra-wide 10x50s on the drawing board?). The best now (NL Pure 10x42 and SF 10x32) are up at 390, so that's still a step above.
It would be good to see more direct Nikon vs Maven comparisons of the HG 10x42 vs B1.2 10x42 and the HG 8x30 vs B3 8x30. On the latter pairing, the Mavens are significantly cheaper, but also an older model than their latest offerings (B1.2 / B6). From the few comparisons I've seen, opinion is split.