The main problem was the missing second stick. It was well built, but for game where a controller is nice touch pads sort of suck compared to a stick and for games where a mouse is nice touch pads sort of suck compared to a mouse. So the only real advantage a touch pad brings is in an environment where you can't bring a mouse. I really liked the extra back buttons. with two sticks that is where all the face buttons should be, on the back.
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.
It's the only controller I use (bar the Steam Deck's built in controller) despite owning plenty of other conventional controllers. Once you get used to it and make use of Steam Input's per-game customisation and mapping it works really well, especially if you treat it as a mouse-like input rather than conventional gamepad.
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.
Its an odd one; the v1 controller feels cheap and definitely isn't as high fidelity as a modern PS5 controller. It struggled to match the quality of contemporary controllers at the same price point. But the touchpads worked. They shouldn't work, they should be abysmal, but with a little practice they're fantastic.
I still use mine for any driving or flying in games, the stick it does have is super accurate. And for watching movies its a great remote when you arent at the keyboard. If you turn the right pad to simulate a weighted track ball it is what I consider the best Dark Souls controller.