This is pretty normal for me on T-Mobile out here in San Francisco on my One S. And the fact that it's unlimited makes it even better. I usually average around 5GB a month in usage by the time my bill comes around. Then again, I never use WiFi because I want the $30 worth of data I pay for.
With those speeds, I don't really see the need for LTE just yet. Oh, and I will be purchasing a Nexus 4 directly from Google. Anyone want to buy like new a One S?