I've had a pair of B1.2 in 10x42 for a week now so here is my preliminary opinion: these are amazing. Now granted, this is my first high end pair of binoculars, but I find absolutely nothing to find fault in. The build quality seems excellent; the eye cups have crisp adjustments, there's no slack in the zoom knob, and the diopter ring has stayed put. The other pair of binoculars on my short list in this price range was the Zeiss Conquests and these Mavens feel better in the hand.
Comparing the view to my pair of C.1 in 8x42 that I've used for the last year, these are superior in every way. I've gone from having a distinct looking through a tube view with the C1s (yet still good for the money), to a very immersive view thanks to the wide FOV with excellent edge-to-edge clarity. The depth of field is much greater on these also. I've done some pre-dawn and post-sunset viewing and in both situations the B1.2 had no issue picking out detail at distance in low light. There's also plenty of eye relief for an eye glass wearer like myself.
I'm heading out to WY for antelope in a little over a week, so I'll update this if I find something to criticize them about, but so far I'm very happy with my decision to get these.