Field of view.

Wider field of view is nice. But it can be designed into a headset in two different ways: better lenses (good) or reduce binocular overlap (not so good).

BigscreenBeyond 2 has used the second, not so good method. The headset is so small that its hard to fit big lenses and the BB1 had narrow field of view for that reason. So the two images (left and right) are further apart on the headset screen and you eyes have to compensate.

This type of being further apart has nothing to do with the the inter pupil distance of the lenses on the headset, it is instead the distance is on the screen, not the lens. Think of it this way: A viewmaster film camera has their two lenses 65mm apart. So does a Viewmaster viewer. Some deluxe Viewmaster viewers has movable lenses to match with your eyes pupil separation. This can adjust for your eyes, but it can't adjust the actual two images on the film which were made by the camera. The only way to do that would have been to move lenses on the camera, not the viewer. A wide or a narrow overlap on the film caused by the camera lens separation is binocular overlap. A wide or narrow separation on the viewer lenses in Inter pupil adjustment spacing, which all VR headsets have. When you buy a Viewmaster reel, it's too late to change the binocular overlap because that was set by the camera lenses separation. But you can change the inter pupil distance of the viewing lenses.

Having a lot of binocular overlap is important mainly for those people who have tired eyes viewing VR. Otherwise it's not so big a deal.

BBB 2 has gained a very much wider field of view than the BBB 1. At the expenses of decreased binocular overlap.

One place the BBB 2 is very much better than BBB1 is in a combat simulator (like DCS). You need to see the enemy off to the sides even when looking ahead, so that you can react faster. In MSFS it's also nice for admiring the scenery, you will see more of it all the time in the BBB2.