Google Project Fi subscribers just got a new featured that Google is calling "Bill Protection." With Bill Protection, those that consume more than 6 GB of high speed data in a month will no longer have to pay $10/GB for each additional GB of data that they consume. Instead, their data charges will be capped at $60/month and data will be unlimited. Unlimited talk and text is still priced at $20/month.
Like all unlimited 4G LTE data plans, Google has placed some speed limitations on its unlimited Project Fi plan. However, Google's policy for unlimited data is different from most of the competition. Most of the competition only temporarily slows down a subscriber's data speeds once they have consumed more than a certain amount of high speed data in a month and only if the network is congested. In the case of Project Fi, users will be limited to a maximum of 15 GB of 4G LTE high speed data each month before speeds get reduced for the remainder of their billing cycle.
Google has not stated on the Project Fi website what speeds get reduced to once the high speed data has been used up. A representative through customer support chat however was able to tell me that speeds get reduced to 256 Kbps. If you want some idea as to how fast that is in the real world, see my review of Ultra Mobile. Those that don't want throttled data, can continue to pay $10 for each additional GB of high speed data that they need. As always, those who consume less than 6 GB of data in a month, will get refunded for any unused data that they have in their accounts.