The Switch has absolutely nothing going for it.
The 3DS at least has 3D screens, dual screens, a unique OS, and an unmistakable design. You won't get that anywhere else, and that's why the 3DS is special.
The Switch is a tablet with two removable controllers, and that's literally it. Even the OS is barebones and minimalistic. It's almost completely text based!
The gimmick of the Switch is that you can play games on TV or on the portable, but they're JUST screens. Playing it either on the portable itself isn't any different than any other portable, and playing on TV isn't different than any other console. It is literally a device to play games. Nothing special about it. And yes, I was hyped as fuck for months for the Switch, but this is just the truth.
I'm waiting for a redesign for the console, I'll buy it day one. The current design just doesn't work. An (actual) gaming tablet with a bluetooth controller is more functional.
Furthermore, the Switch is a pain to carry around, the screen scratches easily and isn't protected by clamshell, amiibo functionality isn't as functional nor immersive as tapping it to the screen, (who thought tapping it to the right analog stick would work well...?) and what hope I still have in the OS is crushed by its many bugs and game crashes. Even the 3DS was more functional at launch. I haven't ever had a game crash without the assistance of hacks on 3DS, and that's since launch. For Switch, it's nearing 6 crashes and I only had it a month.
In fact, it isn't just crashes that make the Switch feel like a glorified tablet. There is video stream hiccups, a minimum required charge if the Switch battery reaches zero (you can't just plug it in and keep playing), the entire basis of Sleep Mode is the exact same as on a tablet (and you don't get StreetPass functionality either).
The 3DS will always be the better console unless the Switch gets a physical redesign.