I played it on a Nintendo Event yesterday. I was not impressed. Same for my girlfriend (and she is an avid user). It was all underwhelming.
Mario Kart World feels and plays as Mario Kart 8. Yeah the track is now one long track and not laps. And 24 players is okay but that is about it. I played Civilization 5 with the mouse, the mouse was okay but that is all I can say, feels gimmicky, the loading took forever. Also the game Drag x Drive is weird. You are controlling someone in a wheelchair but it's also Rocket League. Very strange. You need two joy-cons in mouse mode for this. You use them like you would controlling a wheelchair, felt really bad and gimmicky.
I played Cyberpunk 2077 and Yakuzo, both ran not great. It felt slow and framedropping galore. I did not play Zelda because that game is still awfull, ugly and empty. Donkey Kong is just Super Mario Oddysey but with Donkey Kong. Feels like a mod.
Jamboree TV will get neighbours angry, with all that screaming you need to do in some mini-games. You need to scream so loud, it's insane. Weird choice for a mini-game imo.
The screen is okay, I guess, for LCD. The weight of the Switch 2 is fine. It's a little heavier but not insanely. The new Pro controller is nice but not that different, buttons on the back are new. All in all, it was fun to see the Switch 2 early but nothing groundbreaking. I went home rather quickly, because it was so meh.
All this did made us decide to cancel the pre-order and wait for like a year or so, to see if something good comes out or there is a reason to buy it. And I heard more people say this after the event on the way out.
Below quick photos I took during the event, some kind of proof I was there, haha.