A slightly different definition of “best” is Verizon’s Visible division. NO caps. Just slightly deprioritized speeds 100% of the time. Their website says 5Mbps speed cap at all times but I’ve tested 180Mbps and that was after using like 30GB on my hotspot. Basically all-you-can-eat (including the hotspot) with a risk that sometimes it’ll slow a little compared to others on the network, for $25/mo.

There's a real big difference between "one byte over the line and you're on a 56k modem" and "if you exceed your cap, you're deprioritized to last on the cell pole". The latter is how it should be implemented.