Absolutely worthwhile. Vastly improved braking feel.
HOWEVER, after having had a few sets of the Z1 lines, I would personally recommend getting Goodridge SS lines, unless they are significantly more expensive than the Z1 lines
Goodridge Steel Brake Lines 370Z
The Z1's are fine, and do the job, but I had some issues with seeps and leaks, which I think simply comes down to how the fittings on the Z1 lines are designed.