I've already compared the Zen Ray ED to an SE (search the forum
) and the ZR ED is not better optically. It's close but the SE has the edge optically though almost but not quite as good in color though it is very good for a non-ED bin. And the SE has much better off-axis stray light suppression.
But to link to another thread the Zen's are really (JIS7) waterproof: you can drop the Zen in water and have no problems. You can do that with the Zen Ray. You can't with the SE. You can wash a Zen under a running tap or in a sink full of water. You can't with an SE.
Ergos are different too. The SE is famous for the EP pickiness (needing precise centering on the eye) and excess ER compared to the rubber eyecups. Part of the trade off in the EP design to get the optical qualities they wanted. These are not issues with the Zen. And it is easier to hold a roof prisms steady (especially and open bridge roof) than it is a porro even though the SE is better than a lot of porros out there (a proto-open bridge with that gap at the hinge). The focus on the SE is slow mainly due to higher tension. either of these are warbler bins but the Zen wins this one. Both get stiffer in the cold.
But talking about 10 year old "alphas" comparison. It knocks the Zeiss Victory 8x40 into a cocked hat. Better sharpness, better color and better image contrast/on-axis stray light in the Zen. The Victory is fractionaly brighter (though AK prisms do help). Though I've not tried them I expect the same of similar era non-ED top bins except the difference should be rather less (as the Zeiss was consider the weakest of the Top 4 at that point) though the difference in color and sharpness, I think, should be obvious.
Ultimately I like both the Zen and the SE. Perhaps the SE more as I have both 8x32 and 10x42 but only the 8x Zen.
Used SEs are great value if you can find them at a good price.
As I've pointed out many times: all bins are compromises. Make your pick of the properties you like and get that bin. Or get more than one