Going to be costly and limited. I am willing to bet that this new E-DTA technology won't give permission to stream HD signals unless one has paid the comcast "HDTV technology fee" for an additional $10/mo. The E-DTA will probably be limited to a single stream at a time, and may be considered an extra outlet so add another 7-10 dollars per month. How DRM encumbered the DLNA protocol and whether or not open source applications like MythTV will be blocked form using it remains to be seen. It still doesn't change the fact that everyone else who uses ClearQAM will be completely screwed once Comcast starts encrypting the locals.
The good news is if the E-DTA becomes more than just vaporware it could be proof of concept to the FCC that the model of having one cable box per TV or DVR is now obsolete and streaming video over a LAN via to a customer owned client device is now a viable option and should be mandatory to provide to subscribers as an option.