Like a Segway, I feel like it would be fun to try, but I highly doubt I would ever buy one.
The problem with the Segway is that it can Mame a full adult, and almost certainly kill a small child.
Then people started "modding" the Segway to give it more power.. ~12-15mph.. That's pretty fast for 260lb machine + 150lb rider.. 400lbs coming at you at ~12-15mph
That's why they were banned on walkways..
The final problem is that they're still too slow and unsafe for "streets"..
Thus, there is now no where to go.