"As I mentioned I have tried the SLC 8x56 alongside the rest of the SLC and EL range and I don't recall anything exceptional about it's brightness, sharpness or colour rendition."
With the SLC 8x56 it is not so much about brightness, sharpness or colour rendition all though it is excellent in these areas. Where it surpasses smaller aperture binoculars is in the quality of the image. It is more about the clarity ,transparency and aberration free image it produces. It feels more like you are not looking through a binocular than any instrument I have ever used. It surprises me quite frankly you can not see that when here are four experienced birders that observe it but as you say all of our eyes are different. Henry's quote is on the Zeiss 8x56 FL which is still on the same format.
"Because it isn’t only about brightness. It’s about the quality of the image, and Swarovski’s 8x56 SLC offers perhaps the best image that I have seen in any binocular. Despite their considerable weight I found them almost impossible to put down."
"I looked through the 8x56 SLC at the UK Birdfair last year I thought it gave me the nicest view I have yet seen through a binocular."
"Good as the 8.5 SV is (and it's really very good, better than the equivalent SF to my eye), the big SLC is better optically I would say but you are giving up a fair amount of handling and weight for that image improvement. The SV is my general 'go to' binocular in most cases but I use the 10x56 when I know I need that bit more power/clarity and there is no doubt in my mind it's the better option for tracking very long distance raptors or following a fast flying bird over a darker cluttered background. FWIW, I thought the 10x50 SV was seriously good too but the SLC is just that bit better for me, albeit in a much larger package. The 8x56 SLC arguably has a yet better image"
"Now, does any of this matter when you simply look through the binoculars at 8x? To my delight the answer is yes. In daylight he 8x56 FL produces the sharpest, cleanest and most transparent image I’ve yet seen in a binocular. It’s very obvious comparing it to other binoculars tripod mounted, but even hand holding I’m always aware that the image is unusually fine by binocular standards. I wouldn’t have expected any binocular to make the 8x42FL, Nikon 7x50 Prostar and 8x32SE look mushy and dull in sunlight, but the 8x56 FL does it. Besides the reduced longitudinal CA and SA seen in star testing there is also a reduction in lateral color that is quite obvious in daylight. Lateral color is probably almost always what people are seeing when they complain about “color fringing” in binoculars. There is also a modest but welcome increase in the size of the “sweet spot” compared to the 8x42FL. Less lateral color and a bigger sweet spot are two more benefits that come from the higher objective focal ratio, because the less steep light cone allows the eyepiece to perform better off-axis. But, alas, edge of the field astigmatism is still this binocular’s weakest performance characteristic, just like the 8x42FL. The 7mm exit pupil also has a benefit in daylight. There is virtually complete freedom from “flare”. When bright reflections from the edge of the objective reach the eye they are out at the edge of a 7mm circle of light, so the flare tends to fall invisibly on the iris rather than entering the eye."