The box looks good if you like XBMC. However if you want to cut the cord, there is no tv turner card in that box. You can build a system for not too much more money if you keep the OS free. Such as MythTV.
You can then use a XBMC plugin and and have all the features of the g-box and more. If you want to eliminate your cable bill but still be able to watch your favorite team or shows on the big networks, I suggest a different setup. Personally, I use a windows7 setup with media center as a DVR and a roof antenna. I have xbmc and use it primarily for an addon called navi-x. You can scroll through thousands of tv shows and movies for free.
I plan on using an antenna and complimenting that with this box running XBMC.
You can connect an external hard drive to the Gbox to use as a DVR.