I've had 8 Kowa-8s (also 8Bs in there). Sample variance is huge. Flares can be all different colours, sometimes matching front to back, sometimes not. Some are much sharper than others even when tuned (normal with all scopes). I kept these in the shadow a long time, but when I first stumbled on one I couldn't find even one picture of one on the internet, or even a single word that they existed, it felt like digging up treasure.
I've made some videos with them, but prefer the isco 8s too be totally honest (although how wide a kowa8 can go if you know the right taking lens is pretty amazing).
This whole film I shot with Kowa-8s -