This joystick fit perfectly into my old OEM controller. The joystick is somewhat shorter than the old N64 joystick, and has a soft rubber feel, as opposed to hard plastic. It's more like the joystick for a GameCube controller. This is fine for me, but some people may prefer the older feel. The installation was easy, the joystick even comes with a small screwdriver, and no soldering is required. It took me about 15 minutes to install.
My only complaint is that the joystick clicks in, like a PlayStation controller's L3/R3 buttons. The N64's (and even the GameCube's) controller never had this functionality, so I'm not sure why they included that feature in the replacement joystick.