I've been noticing that 4G throughput in various contexts is pretty mediocre. With 1-2 bars, it might as well be no service. 3 bars is okay, 4 is good, and 5 bars... I don't remember seeing 5 bars.
I'd say I pull downloads of about 22-25 Mbps and uploads from 1.5 to 3.5 with at least 3 bars...