How big is it?

If my memory doesn't fail me I am operating on a 256GB right now. Funny enough I went on a spree re-downloading a lot of stuff since I had to migrate switches and I wanted to have at least the shortcut on the switch itself. In the process I spent a lot more GB than I expected and got the too-full-to-download message.

It is not a bad size at all and I'd still recommend it, however after that experience I seriously wouldn't mind one bit to increase my limit and maybe double it if I can get away with it, haha. I remember the 3DS had a "limit" of size, where if your SD went past it, it would still save your data but wouldn't know how to display correctly when organizing stuff within the system. I honestly wouldn't like to go over the limit but I haven't heard anything similar happening with the Switch.