I pulled the plug on my Genie Go box this weekend and followed suit using the TRANSC0DEON keyword search to enable the internal option on the HR44.
I tried both live and recorded streaming to my cell without wifi and it worked great. I think they are finally getting close with this product, what it should have been 2 years ago.
I do have the Mobile DVR service on my account as I had the GenieGo prior, so it worked perfectly. My guess is if one didn't have the GenieGo previously they may need to wait until launch.
I'll have to try it out a bit more over a month or two, but it looks like the capability is finally enough that I could retire my slingbox.
From Directv.com/mobiledvr:
Mobile DVR is currently only available to residents of Arizona, Colorado, Florida, Massachusetts, Maryland, and Pennsylvania. If you don’t live in one of these areas and you’re excited for Mobile DVR, the Mobile DVR program is expanding and will most likely be coming to your area soon.