Can't blame the hardware entirely when it comes to Verizon and the GS3.
I've said it before and I'll say it again... CDMA and LTE was never meant to be paired together. They are two totally different network architectures and getting them to play nice together requires quite a bit of technical voodoo and sometimes that "voodoo" doesn't always work. CDMA requires completely different provisioning hardware from LTE.
So no, I don't blame the device for the issues. I blame Verizon's poor choice to stick with CDMA when they should've gone with GSM years ago when the rest of the world went GSM too.
They are stuck between a rock and a hard place. Keep with CDMA2000 which has no future or try to develop a way to transition to something newer, in this case it's LTE. But, in the process of doing that you have to create a way to transition over. The faster Verizon dumps CDMA2000 the better it will be for everyone on that service.