Favorite: Steam Deck, it’s my favorite piece of gaming hardware I’ve ever owned. The controls are fantastic, it’s now frustrating to use other controllers that don’t have back paddles, gyro, or track pads.
Least favorite: cheap off-brand controllers, with bad tactile buttons, sticking buttons, analog sticks that drift, analog sticks that only register 8 directions, etc.
Also, Wii U. I have some mixed feelings on it because I have some good memories with the system, but the hardware never paid off. Their were almost no games that made use of the gamepad screen in a way that wasn’t just a gimmick, generally the only real advantages of it were being able to play on a handheld screen while the TV was being used (a feat that the switch and steam deck so far better) and being able to have split screen multiplayer where the players can’t see each other’s screen (limited because you only have 1 game pad, and the deck struggles to do two different rendered screens for many games, with games like Hyrule warriors having to cut the enemies in half when doing split screen).