Hi! At one time these were THE American 'scope long before Leupold and even Redfield. They were used on American sniper rifles in WWII and even, some, on British sniper rifles in WWI. But like a lot of things today's Weaver isn't necessarily the same as yesteryear's Weaver. So, in their day, they were a first rate quality USA 'scope. As good as German of the same era? Well what, in optics terms, ever was!
So please come back and be a little more precise as to the make and model that interests you and I am sure that you'll get another response. Also try some of the USA Forum. I adhere to
http://www.accuratereloading.com and even if you don't join you can still use the saerch facility to peruse their optics notice board.
How do Weaver rate today? Those guys will know!