Mechanical linkage gives a better feel for clutch engagement, a hydraulic has very little feel. Mechanical linkages wear and get sloppy. The hydraulic is, well, another hydraulic system in the car. The z-bar linkage may interfere with headers & stuff--I never had one on my car, but looking at others that do, it is a bunch of mechanical linkages in the engine bay that look like they would interfere with things. I would have to remove it to take my headers off & on. Hydraulic needs a place to mount the master cylinder. You may not have a mount on the frame for the z-bar pivot. I didn't and it needs to be welded on. The other side bolts to the engine with a bracket.
I'm happy with my hydraulic. A bit harder to install initially, but once it's in it's simple, clean and works fine.
Just my thoughts.
Kill the Buddha