Looks like there's no competition here - Verizon is dominant. Even when it comes to price, they're not much more expensive, and actually cheaper if you've got 3+ members on a family plan.
It's really weird that there is that restriction because all of the other 4G phones on Verizon can do simultaneous voice+data. Must be something weird about this new all-in-one qualcomm chip they are using.
This is SUCH a bummer. Honestly, I'm really happy with my iPhone 4. The one feature I was excited about was LTE and the promise that I'd get simultaneous voice and data on Verizon (I had an AT&T iPhone for years -- VZW service is vastly superior in Oregon). Now I'm seriously considering an Android device. If only I weren't so deep in the Apple ecosystem.
To be honest, that use case has rarely come up for me, if at all. I'd much rather have the confidence that I'll be able to make a call (something you have with Verizon, but not with AT&T).
I guess that matters for some people, but do you really use your phone to call people all that often? I'm still on my parents' family plan with 700 shared minutes and we rarely run out. And I'm never leaving the plan either, because I've got grandfathered unlimited data, which is a dream come true on Verizon, especially with a Galaxy Nexus running Jelly Bean.