Wow, $75 for 15/3... I wish them well but that is seriously not competitive at all.
They are getting real unthrottled results from their users who have had similar speeds from Spectrum / Timewarner / Optimum.
I think their pitch (at least a few years ago) was that they would deliver the actual speeds they are promising equally.
I'll admit though I was paying $100/month for 300/15 in Bushwick before I moved. It's probably hard to remain competitive.