Back then, when news of the PS3 releasing was still fresh and the PS2 was already set to hand over its throne, I remember gawking at a custom design PS2 controller sold in a store nearby that was fully wireless, one of the first for its kind. Me being a kid at that time, my reaction to that controller was that I HAD TO GET IT, so I saved up my pennies and bought it for around 36 USD (worth 45 USD today when accounting for the value of the dollar at that time). That thing worked like a charm when it does, but I do remember the occasional drops in connectivity, the random button mis-registers, and the battery life (AA batteries) going from full to zero in between 2 weeks to a month. It had rubber grips on the side which wore off after a year and felt icky to hold onto at that point. This was when the PS3 got fully released and the sixaxis/dualshock 3 was prevalent, making wireless controllers for previous systems less appealing and seem more like a novelty item.
I loved that controller despite those issues but unfortunately, I've lost it and I've gone to just using knockoff wireless PS2 controllers for my current set today. At least the ones I am now using retain the shape of the standard PS2 controller, so the button layout is more familiar to me if anything.