Some of the Kahles scopes are "Americanized" meaning that they have 1" tubes. These scopes are less expensive than their 30mm offerings, but, in my opinion, offer the same clarity and resolution as the Elite 4200s.
In fact, I read one article on the internet that used a special machine of sorts to objectively measure resolution and/or brightness. It was measured by SOAs or SOS, or some acronym like that. In any event, higher is better, and of all of the 1" tubed scopes tested, the Elite 4200 and Zeiss Conquest had the highest SOA at 3.3. I don't remember what the Kahles had (again, the 1" version) but it was lower than the Elite 4200 and Conquest.
Unfortunately, I don't have any personal knowledge about this type of testing, nor its accuracy, but I'm just passing it along for what it's worth.
Zachary