I've bought a Nexus phone every year since the Nexus One (and a few tablets as well) and throughout those years have received a few warranty replacements. One was even a free replacement of a replacement more than a year after the initial purchase. I always get a human in a chat or phone call without any effort, and I always get free next day shipping. I bought Nexus protect on my current phone, and although it is through a third party, when I damaged my phone the replacement process was basically the same (except I had to pay $79). I personally think their hardware support is awesome.

I have used Google's hardware support before for Nexus - and they have been excellent.

Very responsive, and yes, a real customer service agent picked up the phone.

I'll add my voice to those who've had only excellent experience with Google Nexus customer service. Real person on the line, went out of their way to fix a problem that was entirely my fault.

  And who is the servicer of broken phones? Is there a 
  warranty? Can I get a customer service agent on a real 
  voice line?

This was one of the things they announced; Fire-phone-like support tools and access.

I wanted to confirm a change of address for a phone order when i was moving, and got a real person on the line very quickly. American (probably) too, which is appreciated. Not knocking foreign support, but when i call Comcast, there is definitely a bit of a language barrier.

I had an issue with my Chromecast and felt it was defective...yes, that little $25 device. I called up the support line, got an American (at least, someone with an American accent) and went through a few steps. I didn't have to twist their arm to send me a replacement or anything. It was resolved within 10 minutes (though I recall there was a wait).

I would hope they have the same support, or better, for their more expensive hardware.

Did you watch the announcement? There is a built in support function that lets you call or chat with support AND share your screen with them to troubleshoot.