I agree. I sold the BR2 as well for that same reason….size. Unfortunately, though the new BR4 is smaller than the BR2, it is still quite a bit larger than the Sig. I doubt, though am not certain, it will fit in my AGC bino harness pocket for the rangefinder. If they aren't drastically different enough based on software capabilities, then size once again becomes a major factor. Let me be clear. I have not held either in person so I am strictly going off of stated dimension specifications form their respective websites.
Still shocked there isn’t a YouTube video doing a head to head of these two devices yet.