Recent anecdotal evidence of throttling AT&T data speeds on unlimited LTE plans have been confirmed by spokespeople, despite regulatory pressure to eliminate the practice. AT&T users with those subscriptions are still being automatically throttled after they hit 5 GB of usage. This change can be as dramatic as a dip from 23 Mbps to 0.1 Mbps until the end of the billing cycle.
AT&T reserves the right to slow down transfer speeds in the name of managing congested networks, which was the core of their breathless defense when the FTC up and sued them for this kind of thing. As it stands, however, AT&T can slow your LTE speeds regardless of network congestion, and based solely on your "unlimited" usage. Customers on legacy unlimited plans with non-LTE phones are being throttled after 3 GB, but only in congested areas. AT&T plans to factor network congestion into the policy on throttling LTE unlimited plans sometime next year.
How many of you guys are on an AT&T unlimited plan? When was the last time you experienced noticeable speed reductions?