Board 8 > To be clear, BotW in handheld Switch mode is the best for framerate, right?

(+) Yeah! (+)

Waffling whether or not I should buy the Wii U version.

Correct

you'll still get framerate issues with the Wii U version, just in different areas from where you'll get them in the Switch version
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Portable > Docked > Wii U for performance according to Digital Foundry.

Docked has the same issues as the Wii U version but suffers them in fewer (and entirely different, oddly enough) places. Also looks a little prettier as a bonus thanks to the resolution boost, but it's not a huge difference. Portable is a locked 30 fps 99% of the time so performance wise it's the best way to play.

Playing the Wii U version myself and it's still a perfectly fine way to play the game.
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