Welcome, magenta1475682, thanks for asking! T-Mobile ONE Prepaid's unlimited high speed data is a great choice, but depending on how big of a big data user you are (like, are we talking Hercules big or BFG big?) and the area where you're located, you may experience slower speeds if you reach a certain threshold and you're in a location where the network is congested. Our Prepaid Individual Plans page explains that the current threshold is 30 GB of high speed data in a billing period.
* Is the T-Mobile ONE prepaid really unlimited data
or will it slow down after some, like before?
I am a big data user....
In addition to what Marissa said, I would also like to mention. . . .
* When a person reaches a monthly cap on a limited data plan,
the data is subsequently throttled for the entire remainder of the billing period.
* Under an unlimited data plan, when data speed is slowed due to network congestion,
it is not necessary as slow it would be when reaching the fixed monthly limit under a limited data plan. Furthermore under an unlimited plan, if after reaching 30GB, the network is temporarily congested any reduction in speed would only be temporary until the network ceases being congested. Speed reduction would not necessarily last for the duration of the billing cycle.
"Big Data User" Solution to Temporary Data Speed Reduction :
In the past I have had a limited data plan which included tethering. I also had no (land line) Internet service at home. I budgeted my data usage to make it through the month without speed reduction. In some cases I was out of data for the last few days of the billing cycle. Those days were then spent using Denny's or McDonalds free wi-fi. I avoided camping out at either restaurant during peak hours, and tipped well in exchange for hours of free coffee refills. In order to be a good (valued) customer I would make sure I would have at least one complete meal per visit.
The good news about unlimited plans
is that in the unlikely event that data speed is reduced, it would be
a simple solution to visit a free wi-fi location until network congestion
subsides or the end of the billing cycle is reached. Whichever comes first.
Another remedy for data speed reduction in the rare event that it does
occur, is to drive to the vicinity of the nearest uncongested tower.