Can't beat the Performance or Value
The Srixon Z-Star is fantastic!  Compared to the Z-Star XV it feels much softer.  I don't feel as if I lost any distance either.  So, if the Z-Star is soft feeling and has great spin into greens (on edge of being too spiny from mid irons), and great distance then it's a no brainer.  I love the Z-Star.  It's a better performer than Chrome Soft.  It's about even with TP5 but much cheaper.  So go with Z-Star if you want all the performance, perhaps, without the name recognition.
I got it with XL Align and it has helped my putting immensely along with my training Wellputt mat I've gone from 2.33 putts per green to 1.78.