This is a tough one but I'm gonna go with Sony, despite not being a fan of half of their consoles. I do love the PS1 and the PS3 (never had any love for the PS2 or PS4) and I think PS5 is their best designed console ever in terms of engineering, but overall I am a big Playstation fan and have always been since day 1.
Nintendo is a bit trickier. I was never a big Nintendo fan in the past. During the early days of NES and SNES, I was a Sega fanboy and played most of my 8-blt and 16-bit games on Master System and Mega Drive. I didn't really care about Nintendo until the Gamecube, it was an awesome console, but after that I lost interest in Nintendo again with the whole Wii-era. But with that said, they struck gold with the Switch, which is probably my favorite console of all time and I'm hugely invested in the platform. I love it so much.
Never had much love for Microsoft or their hardware (sorry Xbros) but they do occasionally drop some bangers, and since I've recently invested in a PC, their support for the platform is great as well as providing good value with their subscription model, something I can't say about either Sony or Nintendo. I very much want them to stay competitive and it would be a great loss to the games industry if they were to exit.