Did anything transfer from PS3 to PS4 or 360 to XB1?

1) You don't know that yet and hints from reggie interviews suggest there will be some transfer policy as they are tied to the account not system.

2) I am buying NS knowing that there is no BC. So while I would prefer that digital content can transfer, I am prepared to accept it won't and that I won't re-buy any VC content again but instead keep my WiiU.

Yeah, but all the cool kids will be playing it on their NS...

Did you like the DS/3ds? 

I have a Wii U and I'm definitely getting a Switch on launch day.

I don't know. I know that cross-buy between PS4 and Vita is pretty robust and that XBox One adds newly compatible "backwards compat" games pretty often.

But those systems don't have the 30 year legacy backlog that Nintendo has so I guess I pay less attention. 

I bought the U on launch, so I feel like I got more than my moneys worth.  I have a bunch of great content that I haven't finished yet.

i was kind of salty once nintendo starve the late years of the gamecube to hold games over to the wii. then i was kind happy in the early years of the wii. then i became horribly salty when nintendo had a mega sucessful console and still managed to abandon it after only a couple years of support.

a promise from nintendo is about as good as one from donald trump.

I wouldn't say I'm salty, the main reasons being that I didn't buy it at launch, and cause Zelda wasn't one of the games that made me want to get one.

I got out tons of playtime out of it thanks to Smash and Splatoon.

The. Best.

Wintendo. Bigly.