The keyboard itself is irrelevant. I'd recommend getting a keyboard without labels to free yourself from the idea that you need to look at them.
All of the time? I don't get this. There's no problem switching between Dvorak and Qwerty if you do it regularly. It's like switching between bicycling and snowboarding.. you just switch the context for your muscle memory. Although you'll probably have a bit higher error rate on the layout you use less