I seemed to notice the last couple months after I get the messages my service drops on download (but not on upload). I drop to their 5M connection instead. Strangely when I check known download speed sites they work with correct numbers, when I check other means I notice the difference there. So I hope they are not nerfing me wholly except when I try to measure it with known tools i.e. speedtest.net etc. They seem to be nice about it now but who knows, this is the first time they have been as vocal about it.
Sadly the next two tiers (yep we are there) only add 50GB (300) and 150GB (400 total), with the speeds of 25Mbps and up to 50Mbps but if you have higher speeds you will download more and be on HD more, get more files, backup more and always go over.