How well does Partners in Time work on Wii U VC?

I've heard mixed thoughts about DS games on Wii U VC. Some games, like Yoshi's Island DS, are outright unplayable on VC, while others like New Super Mario Bros. seem to work fine (sans multiplayer). Where does Partners in Time fall here? I've heard that some battles and Bros. Items don't work properly without the default display method with tiny screens. But is this a minor problem, or is it game-breaking? Is it worth the extra money to get this on DS?

I'd sooner buy a cartridge off amazon.

In fact thats what I did. The wii u port is rubbish.

Emu latte, baby, especially if they give little shits about their customers.