Had a short conversation with some of the DirecTV marketing and engineering team the other day about the wireless genie, here are a few interesting points:
Any wireless install uses the wireless video base, which is best to be installed near where the wireless clients will generally be used and away from other wireless devices (like routers).
The wireless video base will be hardwired to the SWM network via coax, but does not need to be near the Genie receiver, it is best placed in a central location to the wireless clients.
A wireless video base can support up to 3 wireless clients.
On unique installs they can use multiple wireless video bases, but that should be rare.
Wireless client performance is "very close" to that of a C41. There is a slight lag, but that is true of any of the clients. They were very aggressive to minimize any noticeable difference.
They tested it in houses as large as 7,000 square feet, it is designed to work in most residential environments as long as the installer considers where the base it put.
Some construction will be a natural block to the wireless signal, like stucco walls or similar construction with metal in them.
These type of things will mostly prevent use from outside a building depending on the construction of the building.
In most situations a wireless video base on a central floor will support devices on different floors (like a basement or second story), if the wireless video base is well placed in relation to the wireless clients.