They've already said it will be $400 (6x Google Fiber price). I don't know why so many articles don't mention this.
The question is, will Netflix still be throttled at those speeds? Will torrents? Because even now people supposedly have 50Mbps, which is more than enough for Netflix which only requires 3Mbps for HD streaming, yet somewhow when they play Netflix it often works under <1Mbps. Use a VPN and it magically starts working perfectly again. Strange, huh?
So yeah, before anyone gets too excited about this, let's wait and see how it actually works, and whether it will actually arrive soon, or it's just another "fiber to the press release" to keep people cheering for Comcast for the next 3 years until they actually start deploying it.