Spoiler alert: you WILL need to contact the offshore, 3rd-world tech support of ComCast/Xfinity to complete your setup. Make sure you have the time for not only someone to help you, but to suffer the frustration of being "put on a brief hold" about 20 times.
The unit works great after all that nonsense and it WILL need a firmware upgrade out of the box. If will have paid back the rental fee of the unit it replaced in 19 months.
Lots of these for sale out there - find the best price and buy it.b