I am going to go out on the limb here and say that MOST existing customers will NOT want to upgrade to the XIP.
The XIP is designed for NEW customers. It is designed so the installer needs to run just a single wire into the house from the dish. From there the installer plugs the XIP into your cable television line and from there you now have satellite distribution throughout your house where ever there is a cable tv line installed. Now the tech goes to each TV you want satellite on and installs the joey box and boom you now have satellite tv there with no additional wiring.
It will cut install times and install costs greatly.
For existing customers the XIP setup will probably require rewiring of some sort, as at the moment each room has a wire coming to it from the dish or switch. You wold need to take the additional rooms and unhook them from the dish or switch and hook them up to cable tv splitters making it a cable distribution network for the XiP to work. I don't see many people wanting to do this. And honestly besides sharing recording on your DVR in all rooms you don't really gain anything that you don't have now.
The big flaw I see in the XiP is if your main XiP box goes out then you have no TV on any of your televisions in your house.
So I think it will be GREAT for new customers but not so much for most existing customers... except for those like us who like to tinker.