GenieGo has been a great solution for mobile DVR. It allows DIRECTV subscribers to offload shows to their smartphones and tablets for viewing outside of home, but it also lets them stream recorded TV programs on the go without a cellular data connection. It's a nice piece of technology, but it's now two years old and there are newer alternatives that do the same job.
Those include a service called DIRECTV Go that doesn't have the same $149 initial charge for the device and charges only your cellular data plan for downloads (and possibly AT&T's $10 per month Mobile DVR data limit, depending on your wireless plan). It's easy to set up and works right out of the box, as long as you have a compatible phone or tablet. It has a cool feature called automatic queue that preps a show for sync as soon as it records on your HD DVR. And it shows an ACTUAL free space indicator, unlike the 73% or so crap that many other devices claim to display.
You can get DIRECTV GO with an ENTERTAINMENT, CHOICE or XTRA Package or higher and NFL SUNDAY TICKET package (subject to blackout rules). Prices include one instant bill credit for 12 months.