Mechanical Quality: they all kinda look the same, is there really a difference?

 Yes, absolutely!

Cheap scopes, on average and assuming the same configuration, are less durable and reliable than their more expensive brethren (although mid-range scopes are not necessarily any less durable than the expensive ones), have less precise adjustments and are prone to other mechanical problems. Now, I am mostly talking about really cheap scopes here. These days most scopes from the mid-price range onward are quite good, but that of course depends on the application and on the user’s expectations.

Oftentimes, it is difficult to generalize about the quality of a particular scope. Besides, there are exceptions to all generalizations, and naturally, those are the ones that people remember. It is an unfortunate consequence of producing anything mechanical that there will be occasional flawed samples that make their way through QC (quality control). Typically, part of the price you pay for an expensive scope goes toward more extensive QC, but regardless of how expensive, all things mechanical can (and occasionally do) break. There is no way to guarantee with 100% certainty that any particular scope will be both repeatable and reliable, but common sense suggests that we can come up with some reasonable guidelines. Bottom line (and this is going to be a rather recurring theme) is that if the riflescope configuration that you are looking at is difficult to make, consider spending more money. Affordability and complexity simply do not make a good combination. Moreover, keep in mind that something considered difficult to make twenty years ago is not considered to be all that difficult today, so this is a moving target of sorts.

However, the general principle holds: it you are looking at a $300 scope with the same feature set as the latest and greatest $4k instrument, chances are that you are trading away some mechanical quality for all those features.

In terms of the mechanics, the things that are hard to make are somewhat self-explanatory, like the high zoom ratio designs that are so popular now: 3-9×42 is easier to get right than a 3-18×42.

Similarly, the higher the magnification of the scope, the tighter the positioning tolerances for the mechanical elements are.

Then there is a case of somewhat misplaced expectations: for example, most hunting scopes are intended to be used in a “set and forget” mode. One implication of that is that the adjustments, although marked 1/4MOA, may not be exactly that. They might not even be very uniform or very repeatable, but, once the scope is sighted in, if the point of aim does not move then the scope works as intended. Finally, there are the economies of scale to take into account: if a particular design has been made for some time and in volume by a reputable maker, it is likely that most of the kinks have been worked out.