I had a Z5. I believe it was a 3-18X model. VERY nice scope. I don't know how much of this trickles down to the Z3 models, but the tracking was excellent as was the glass.
I don't remember which reticle is was that I had, but it was intended to be used a a bullet drop compensator. The idea was to get to know your rifle, ammo and reticle, then use the subtensions as reference points.
Overall, I really liked the scope. In only got rid of it in favor of the tougher build of a Nightforce, although I did sacrifice some glass quality in the move.
On another note, the Z5 maintained its water resistance even with the turret caps removed, which I thought was a testament to the quality of the build. I often find myself wishing that I had kept the scope.
Whatever gripes there may be about the Swaros, I don't think that the glass quality could be one of them.