I have a Swarovski spotter that is absolutely alpha glass and I paid for it. It's stunning. I've compared it side-by-side with $15K Takahashi scopes and it left little to be desired.
I've had the Z3 and presently the Z5 rifle scopes. They're not what I would call spectacular optically but they are good overall for their purpose. The Z3 is a sub-kilodollar scope and at its price point I would expect it to compete with an advantage over the VX-3HD. The Z5 should compare favorably to the VX-5HD. It's noticeably optically superior to lower-end scopes, but it is a mid-market product. Optically, it has a generous apparent field of view. The chromatic aberration is the worst. When I look at a high-contrast edge at higher magnification (12X), I can hardly believe Swarovski produces this. I even sent it back to Swarovski USA and they completely overhauled it but the CA is still bad. It's a twelve-hundred dollar scope. I would advise not to expect it to look like a four-thousand dollar scope optically nor would I expect it to be mechanically as robust. I find it entirely satisfying for hunting. It's lightweight, compact in length, the ballistic turret is simple to use and all that is needed for hunting big game. The erector, turret, and tracking are probably going to leave something to be desired for long range precision that a Nightforce would not but at the cost of another pound of weight.
There is a way out of the optics rat race. If you're like me and can't achieve your big game hunting goals with a flintlock (which would be my first choice), get a quality scope (the mid-range Leupold and Swarovskis are fine) and be content knowing that you have more money for tags, time off work, travel, and observing glass (spotters and binos).