I've been evaluating a few Swaro Z3 and Z5 samples recently. The Z3s are similar in performance to the Zeiss Conquest line, with perhaps higher transmission, Compared to the scopes you mentioned the Z5 advantages are larger zoom ratio, lower weight and higher contrast. The contrast, in particular, is amazing. Vortex PST scopes have mediocre contrast and are not even close. Leupold VX3 and MK 4 are better but nothing like the Z5. I personally like the 3.5-18X44 model with the BRH reticle.
Whether or not those advantages are worth the extra cost depends on your application. For long range hunting in the mountains at dawn and dusk, it probably is worth it.
Depending on your caliber, you may need a biased base to get out to 1,000 yds.