Variants in University H.D. Abbe Orthoscopics ?

Can somebody enlighten me whether there are some variants in these EPs circulating on the market which would make one version more desirable than other ? Maybe barrel undercut or quality of coating ?

David

There is the Standard Volcano Top Ortho, the Flat Top HD Ortho and the new OPS HD Ortho.
The Volcano top uses standard coatings. Easy to use with the short eye relief in shorter F/L EPs.
The HD uses better coatings, according to UO. Flat Top can be less easy if you wear glasses especially, as the flat top gets very close to the eye and lashes.
The OPS uses a special planetary filter coating on one internal lens. Same as above for the the Flat Top HD as far as comfort and use.
Which is better, man, I am still trying to get a straight answer on that question.