My GS3 supports voice and data on verizon. I live in a 3G area still and it works good. I can't see them going backwards in tech. Verizon is CDMA though that's probably why it doesn't work on Sprint. I didn't know the Iphone 5 wouldn't support voice and data, that cracks me up. That's what happens when people buy a phone based on hype and don't do there homework.lol
This is one of the few drawbacks of the Verizon (and Sprint) GN2.
The GN2 uses the Exynos? 1.6GHz Quad-core processor that does not allow SVDO on 3g.
The GS3 uses the 1.5GHz x 2, Qualcomm MSM8960 that allows for SVDO on 3g.
Although I have good LTE coverage in my area I often see my phone revert to 3g in certain buildings or areas.
Luckily my Thunderbolt was the first Verizon phone to be able to do SVDO over 3g. I don't want to go backward so that is why I wish Samsung had used the Qualcomm S4 Snapdragon instead of the Exynos.