I have a z5 and hd5 zeiss, had a 4x12 z3. All great scopes and don't think you'll be disappointed with any of them. I only sold the z3 to replace with the 5-25 z5.
I think the z5 is alittle sharper than the hd5 but very marginal. Both have track perfectly so far. The one thing I like better with the hd5 is the crosshairs are heavier and can see them better late in the day.
If 12 x is enough for you then I would go with the z3, if I wanted more magnification I would probably buy the zeiss and put the extra money on binos.
