I think the 7300 is a little more stout (look at top tabs) but doesn't come with the metal pole to position (tilt/lean) the auger (look bottom right). I like the "guide" pole but it's bent several ways, I would go with the 7300.
the 7200 has the guide rod and a lighter casting of the gearbox. The 7300 has no guide rod and a heavier casting.