I know SDCC is having a digital give away via Nintendo if you do this hash tag smash thing there.
More details here: SDCC SSB4 download give away
I've already played the 3DS version two times and wii u version once at the SSB4 @ BestBuy event. Photo collage
I think the controls are hard to grasp, like super hard! I remember that the c-stick moves on the 3DS version has to used by double tapping the circle pad + some other button.
It was just bad, the Wii U pro controller controls are similar. So, no matter what, get the Game Cube adapter!
It was still fun! I got to face against mega man and little mac. I beat them up with Kirby, lost in the Wii U version though. Huge sword smash action right there for Kirby. But I didn't know how to get other characters powers as Kirby in it because of the controls! I mainly spammed his down b attack where kirby turns into a stone or other item.
If others have tried SSB4 or may question me, feel free to talk here