I guess I'll ramble for a minute. The question for me when considering these outrages prices for eyepieces is what am I getting? A rare collectors set or eyepieces that can actually offer me something in performance I don't already have. The truth of the matter is among the best eyepieces made today what will determine the very tiny differences (if any) in what one can see won't be the eyepiece but will in fact be the atmosphere. It would be so nice to own a set of ZAO's but there is nothing you can see with those that you can't see with others and you would spend a lifetime trying to notice the differences if you think they did offer you more because the differences under perfect conditions would be that insignificant. Patience at the eyepiece with what you have will be your reward.
Don't fool yourself, many of the original customers bought them to use. Mine come out on good nights, but usually for shallow space targets. Since I binoview, I don't bother with the 4mm and 6mm ZAO II ... I've kept these because I want to keep the set complete.
The short answer is these are still the best lunar & planetary eyepieces ever made. You can look through my collection (here) and decide whether it's complete enough to convince you. Of course, you are always sky limited. I find that patience helps, even under sub-arcsec seeing.
From 13 years in Toronto - if you live under the jet stream - I'd not bother.