And for those of you who had neither, what about the Switch appealed to you where both Wii U and 3DS didn't?

Nope. Wii U was the first Nintendo home console I have ever skipped going back to the NES and I've just never owned a handheld in my life.

I got the Switch because I could tell that Nintendo had their act together from their January presentation, I figured a hybrid console would be very popular, and the first year's lineup looked ridiculously stacked enough that I didn't think I needed to hesitate.

I've only owned a Gameboy SP (NES edition) and I borrowed my gf's DSLite on occasion. I've always been more of a console gamer.  The only Nintendo console I've missed was the N64.

Yes, I have both.

I had both, I got a Wii U in 2013 and a 2DS very late in 2019

Both, yeah.

I got the WiiU quite late in its lifetime.

I never missed out on nintendo consoles ever , the only handheld i missed out was DS, and virtual boy , but I did own 3ds/2ds heres proof of my second youtube channel of wwi u games back in 2012 I bought wii u 350 dollars plus tax with nintendo land bundled though I'm only showing wii u games here :)

Both. Many versions of the 3ds. Possibly all of them with any improvement to size?
One of the reasons I find disappointment in the switch.
I already had Donkey kong, Mario Kart, Mario 2D etc. I want the next ones, not the ports.

While at the same time I'd quite like a port of Mario 3d. Remove all the Wii U junk. The breathing, the touching, and preferably Captain toad.
Captain toad is fun in his own game, doesn't work in a Mario game IMO.

Both and I like them more than the Switch.

I preferred WiiU to Switch, though I thought the giant Gamepad was weird. I owned at 3DS, but was never a big fan of it. I think I bought it after that price break near launch because I knew I would be laid up for a while and wanted something convenient to play without having to get out of bed. But, before I sold it in 2018, I probably only ever purchased 6-8 games for it.