Nobody knows exactly what's causing the problem... it could be hardware, it could be software, it could be specific towers, it could be all of the above, or it could be something none of us know anything about. There has been no consistent "clue" yet to point to any specific cause. The test OTA's have had mixed results on the data connection issue while fixing some of the other bugs.
I've seen a few reports of people pulling their sim card, booting the phone, letting it sit for a few, then powering down and reinserting the sim card, thereby forcing Verizon to "re-recognize" them in the system, with success. If it's a sim card issue, that could explain the inconsistency between people/phones/areas/etc. But honestly I don't know if we'll ever know. It could simply be something on the network side of things that they eventually work out and we never get an answer.
Long story short, clearly some people have the issue and others don't seem to, and nobody knows why yet, and both sides of that fence shouldn't be fighting with each other about it trying to convince the other side that they're wrong.