Of course this is a small sampling but I have been trying others' binoculars whenever I've had the chance. I have swift 8x42 roof binoculars and 8x56 Orion porro binoculars(which I bought for astronomy purposes). I have used swaro 10x42 roof binoculars on many occasions. Obviously comparing these binoculars is not a direct comparison but here is what I found. The $300 swift binoculars are brighter, have a better close focus and a faster focus than the swaro's. The Swaro's are a little sharper and have better depth of field than the swifts. Maybe 20% better in those departments.
The Orion 8x56 binoculars are brighter than both and at least as clear as the swaros. The Swaros maybe have a more 3D effect to them if that means anything. The Orions were $160 over the net.(from what I gathered they were made at the same factory as celestrons of the same specs. and are sold as a sort of generic version of the celestrons at a lower price.) Because the swift roofs were more comfortable I wanted them to be better. When I look through the swifts I can get a nice view but it takes more focusing and my eyes have to adjust a little. When I look through the Orions the view is plainly there clear and sharp with perfect detail edge to edge including the background. Of course they are a bit bulky but I plan to use them for birding more often.
Larry,
Your investigation clearly shows that the improvement of light transmission you may count on to get with the best available optics in comparison to much sheaper (but still quality) optics, can't beat the improvement of brightness you get using 5,25mm exit pupil instead of 4,2mm. If having equal light transmission a 8x42 is 56% brighter than a 10x42, and that difference maybe corresponding to compare the Swarovski 10x42 to a nearly uncoated 8x42, or at least a bad fully coated one.
I have earlier owned a Celestron 8x56 Ultima which according to what you describe, likely is the same optics as Orion 8x56, But in the early 90s they were not at all sharp until the edges. It had quite much "globe feeling" when sweeped it.
Regards, Patric
The 8x56's are supposedly fully multi-coated BA-k4 prisms.