The polygon preview said they had hardware problem with the controllers becoming unsynched. That's not good.
So did this one:
Same problem with mine. I think it is only one of the two Joy-Cons specifically however -- the left one. We've reached out to NOA and will update.
We didn't do a video on the unboxing or using the system but more so discuss how it is using it on a day to day basis.
During one part we do bring up two technical issues I have with the Switch, which I'm really hoping are just isolated to our console. One is with the battery not charging all the way even when it's docked, and the other with some issues of input lag in rare cases when the Joy-Con are detached from the console itself.
Nintendo Switch First Impressions - What's Up Games
(To clarify, for those inevitably asking how the hell we got one, this is a press unit for GameZone.com, which will be having a written preview up as well)
Edit: Oh! I see other sites have had issues with the left Joy-Con as well.
Since there was discussion in that other thread about moving this to its own thread
Kotaku's Jason Schreier also reports having that joy-con sync problem.
"Jason Schreier Retweeted Wario64
Yep, my left JoyCon desynchronizes as I'm playing. Gonna be a big problem if they can't fix this with a firmware update!"