There's nothing particularly new about the technology, either. For example, the "standing up on its own" part is something that rockets have done for decades, using the same basic principles.
What this thing really is, is an attempt to define a market niche -- something that fulfills the same basic functions as a bicycle, withhout the need to climb onto same.
As an idea it's not too bad, but there are a number of downsides to this particular answer that make the Segway less than ideal. For example, its range is limited, which means you're probably not gonna commute to work on it. If you do use it in the city, you still have to find a place to park it, wherever you go -- not always easy. And of course there's always the question, "is it easier to walk?" It often is easier to walk -- especially if you're not alone.
Depends on whether you are young an healthy. I suspect this is far more practical and mobile than motorized wheelchairs for folks who can stand but can't walk easily. I look for this to catch on as the boomers get older.