Only issue I see is no sliding glass (that I saw) and looks to be for interior doors (doesn't look like it has the power to close an outdoor-door).
Other then that, I agree, for that price, you can't touch it even building it yourself. Heck, maybe it's on e-bay even cheaper!
It is rated for the weight of an exterior door, but it would come down to how stiff your latch and weather stripping are. Worst case scenario is that you need to replace the latch and weather stripping with a style that has minimal resistance. Depending on the door that may be simple or very challenging.