Heres how it boils down for me.
S13
pro's : Affordabe, light, simple, very easy to work on, parts availibility, aftermarket parts, easy to drive very forgiving, comfortable enough to drive daily.
cons: everyone and their mom has one today, esp. with the drifters.
S14: same as S13 but better looking and better for daily.
Z32:
Pros: rare, herritage, looks like a sports car should look, good brakes, LSD, and other goodies with TT model, handles well.
Cons: confined with space to work, heavy, dont know about now but when I was looking for one they were pricey.