I haven't read through all of the posts, but wanted to share my experience with the same "radio issue."
My first nexus developed a screen issue and was sent back. (It had NO connectivity issues at all.) The refurb replacement was terrible. As were the next 2. At this point I complained enough that they offered me an S3 - with the caveat that I had to pay for a back and battery since I would get a refurb. This was unacceptable... and I was shipped my 4th refurb (5th overall in last 8 months).
What do you know, this one works perfectly!!!
For anyone experiencing problems, talk to a supervisor (and his/her supervisor) until you get either next day shipping of a replacement or an S3.
Still waiting for some sort of response, I called again to inquire. I was forwarded to 'tier2' (which I think is really just tech assistance) who said it would take up to 7 days for a response. He said that the network has to checked, my area 'driven' and a supervisor to review it.
I spoke to tier 2 on Thursday. Nothing helped. Was supposed to get a call back from a supervisor on Friday, no call came. I called today. A supervisor said it was a hardware problem, duh, I knew that. I'm getting a replacement tomorrow.
This guy sent me a few text messages that werent generic or computer generated so hopefully they'll fix it within the next day or so. I honestly.don't even want the Nexus anymore... perhaps if it worked properly, I'd feel differently but right now I just want to smash the phone.