Well those are a lot more money than my bx2 alpines so I would guess they are pretty badass. I love mine even though they are a lower tier I can?t say enough good things about them so far.
Ran a set of 8x42 BX-5's this past weekend at Total Archery Challenge
These were beyond amazing but $1250 msrp
Additionally they are a step up on the polishing scale for your glass.
The BX-4's are arguable to be 1/2 the cost and seemed very well praised from the base of the hill. the 5's were on the hill with me and were superb