well I am on the 6 Mbps plan and this is my results
:::.. Download Stats ..:::
Download Connection is:: 15036 Kbps about 15.04 Mbps (tested with 12160 kB)
Download Speed is:: 1835 kB/s
Tested From:: https://testmy.net/ (Server 1)
Test Time:: 2006/07/09 - 6:23pm
Bottom Line:: 262X faster than 56K 1MB Download in 0.56 sec
Tested from a 12160 kB file and took 6.625 seconds to complete
Download Diagnosis:: Awesome! 20% + : 187.88 % faster than the average for host (comcast.net)
D-Validation Link:: https://testmy.net/stats/id-2Q647AKM8
User Agent:: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727) [!]
The boost really does exist but it is only for a very short time. If you did a bigger download you would notice your speed would drop back down to where it is supposed to be.