Your post prompted me to look at my service. I've had it for 11 years, so it was pre-Power Boost and all that bullshit. I did a test and got 20Mb down and 1Mb up, which seems to be between anything lower than what you got (15Mb up like you said) and what you got, but all it says on my service is "RoadRunner High Speed Online." Maybe I'm grandfathered in or some shit. I'm pretty sure I pay ~$40/month.

