I've had them all and to me Schmidt & Bender makes the best rifle optic, followed closely by Swarovski, then Zeiss. S & B, it's all they do and they do it well. I've never had a S&B lose zero, in 25 years, and the clarity is a lot better than anything from the USA. Zeiss typically loses on eye relief. I don't think Zeiss erectors are on par with Swaro or S & B,.....S&B being the highest quality, again followed by Swaro. I have a buddy that swears by Leica,....but I haven't gone that route as I have too many scopes laying around the way it is, I use only Talley QR rings and bases so my scopes move from rifle to rifle like a camera lens. In the last 25 years I've had to send at least 5 Leupold's back to get worked on. Vortex are garbage and wouldn't buy one for a larger bore rifle - ever. I don't have any experience with Mavin, Arken, Riton or the plethora of others on the market.....but my guess is they are just American design cobbled together with German glass and Japanese components.
As far as metrics, to find someone to be honest in this industry about real quality in the USA, it's impossible. Gun writers and youtubers will review and put forth any angle on anything they get for free...hence I would only trust decades of experience and heed the advice, as mentioned before, "buy once, cry once." In optics you get what you pay for.