I have no experience with the new Kowa BDII, but like GC I also have a 2015 CL 8x30 and find the image very satisfying.
It's not as super sharp as my newly acquired Z FL 8x32. It doesn't have strong/bold edge contrast, but has very good resolution, brightness and I especially like the colors. Lighter tones seem illuminated which makes for some pretty images in the right lighting. FOV is a bit narrow, but the sweet spot is pretty big. Ergonomics are wonderful and the low weight is a plus.