Steam Controller 1 wasn't good IMO and is now accumulating dust.
Somewhat related, but I enjoy the topic. Is how freakishly good the mouse is for FPS type games. If you asked anyone to design a purpose built controller for a first person game they would not come up with a mouse. But somehow despite all odds that thing designed for moving a cursor around the screen is the best controller yet for looking around. Probably something about the huge throw distance compared to any other controller.
The only place it suffers for me is games that aren't coded to support simultaneous gamepad and mouse input, which you can work around by mapping the joystick as a keyboard input. Otherwise it's great.