I have not pre-ordered and I do not plan to unless there is a really good reason to. I'm planning on buying digitally.
Some sites like Amazon likely have it up for pre-order already, but sometimes eCommerce sites will cancel or change your pre-order in a way you don't want before the game is released. I think it's best to wait.
Ah, ok. I have been waiting for it to show up on the Nintendo site. I am torn between getting the cartridge or digital. I usually prefer having a physical copy but lately I have been buying digital instead.