I have a faulty left joy-con. The signal is so bad that even if sitting just 1 meter from the console in docked mode, it sometimes loses signal. I had to buy a pro controller to be able to play zelda on the tv.
No issues in handheld mode. I contacted the national Nintendo distributor and they said the problem only affects some joy-cons, and they'll of course replace it if i return it to the store I bought it.
I haven't done it yet as I would have to be without joy-cons for a few days = no handheld mode, but I'll probably do it this week.
Apart from that, I haven't had any technical problems. I am actually surprised at how slick the system is, going in and out of sleep mode is instant, so it's really easy to to pick-up and play.
My impression of Switch is probably a bit affected by the fact that BotW is by far the best game I have ever played. I daydream about it at work, and I stay up late every night to play.







