I've had some issues with my launch 3DS.
It has the lines on the screen (from folding it shut). This is really annoying.
The casing has cracked in two spots, near the two external cameras. This hasn't caused any usability issues, but it makes me nervous.
My "A" button wasn't registering a press for quite a while. It didn't really feel off, but I would have to press it REALLY hard to get it to register. Lately, it has been working fine, but once in a while, it's just a little bit harder to press than normal (but nowhere near as bad as it used to be.)
I haven't played the Wii U as much, but I haven't had any substantial issues with it yet.
I can't get sound to come out of the surround sound system. My old receiver doesn't have HDMI ports. My Sony HDTV has an optical out, which I have going to my surround sound... but it doesn't play sound. I blame Sony.