Seems like the general consensus is, "It doesn't make it cheaper for my usage pattern, therefore sucks."
This is interesting because it's more about cross-carrier / wifi handoff experiment than anything else. The only reason why this is such a big news is because it's Google, if a no-name upstart was behind this, it would be a blip in the tech world and only relevant in the wireless world.
Pretty much from a purely pricing POV, there are better options whether you are a heavy / light user of data / voice in any combination and I'm sure this was intentional. Google isn't going to make any profit from this experiment and pricing it too low would just get the carriers to not sign on.