The Opticron Aurora is 95% of the Zeiss. The zeiss wins with the edge to edge sharpness and a bigger FoV. The Opticron fades out at around 90% but is still well able to ID birds with ease as your eyes wander the entire image.
Where the Opticron shines is the delightful, creamy velvety palette of colours that bathes the viewers eye. It is far, far more relaxing and inviting than the colder Zeiss, and when you have them over water? The Opticron wins - as something the Zeiss has that stopped me dead, was a brilliant blue ring around the entire image. Bright blue. Dazzling in high glare at sea.
I sold my Zeiss, and I never thought I would ever write that, but every time I use my Opticron bins, I have zero regrets.