Personally I like the clickyness of the gp32's joystick more than the gp2x's non clicking joystick. For me the gp2x's joystick needs getting used to and it also depends on the type of game that you play.
Frodo on the gp2x end gp32: anarchy (hewson), boulderdash, mspacman require 100% horizontal & vertical joystick movements only or your character will move in an unwanted direction or not move at all.
With the gp32's joystick it's easier to only move horizontally en vertically only than with the gp2x's joystick. But perhaps one could improve the joystick readout (the gp2x's joystick does have more microswitches than the gp32's)
Moving through frodo's menus is easier with the gp32's stick than with the gp2x's stick, I tend to ofershoot. Also using the virtual keyboard is easier with a clicking stick....
in games like Hexen, Quake, the gp2x's stick is just great though.
I am an old skool microswitch joystick liker, I preferred the Suzo Arcade clicking microswitch joystick over the spectravision membrane joystick we also had for the c64. My brother actually preferred the spectravision joystick because it looked like the trigger from a fighter plane.