I am on your 3GB prepaid plan, and I am seeing speeds of 0.2mbps at times. Most of the time this is when I'm traveling, even when I have at least 4 bars!
I just read that you prioritize other Verizon customers above prepaid customers during times/places of congestion. What the heck am I paying for? What's the use of having LTE data if I can't load a web page? And limiting video streaming to 480p? Might as well pull out my VHS tapes - at least there's no buffering.