If rackspace isn't a consideration, you'll probably be better off with a Doepfer quad A-143-2 ADSR or the equivalent.

The price is less than the Zadar. The Zadar also has an expansion unit that just came out. I'm not sure of the name. I wouldn't undervalue the immediacy of having a traditional ADSR at hand. Having to menu dive the Zadar might impinge on your workflow. ADSRs aren't typically set-n-forget and I'm always tweaking them to get to the magical sweet-spot. It all comes down to you and what works best for you. It wouldn't work for me. But I'd love a Zadar to expand my capabilities.