It depends. Where is the Virtual Boy featured more: Console or handheld Wario Wares? Remember the first one on both consoles and handhelds negate themselves, since all the microgames are the same.
Anyone know the answer to this?
Anyway, The Virtual Boy requires stationary positioning, has a wired controller, and requires a surface to set it on. During play, it isn't portable at all. However, it is entirely self-contained, with it's own screen(s), so you can take it anywhere much easier than any game console. I'd certainly say it is a portable platform, from its ease of transfer, along with the built-in screens.
Additionally, I personally consider every platform a console, for some reason, and base my categories on what is portable and what isn't. By this virtue, I would say that the handheld would be the way to go for me, personally.
Verdict: It's the Virtual Boy. It and the CDi both go to the Funhouse.