KSagal - I finally tried a Yike Bike! The nice folks from New Zealand traveled to NY for a few days and offered rides/lessons.
My Perspective as a Segway owner:
Benefits Over the Segway -
Flexibility. Sometimes when I am gliding, I come upon situations that aren't best for gliding (heavy traffic - pedestrian and/or vehicle, rough street conditions). In such cases, I'd fold the Yike Bike, then resume riding in improved conditions.
Storage. Being able to take it with me into the office would be ideal. The bike room guard already told me that sometimes they take breaks abd don't watch the bikes *whaat?*
Portability. Being able to hop onto public transportation or into a cab if it starts raining while out is really invaluable for this NYC girl.
Power Failure. If it fails, pick it up and carry it home.
The Segway's Advantages Over the Yike Bike -
Balance. On the Yike Bike, the faster you go, the better your balance...um, no. That doesn't work for me in the city where 'open roads' are something you may see on a screen saver. In NYC, you're always stopping, starting, adjusting speed, ducking and dodging. The Segway is perfect because you can travel as slow as a pedestrian, stop easily, turn 360 degrees and not lose balance as it's self-balancing. VERY important!
Safety. To be fair, I only tried the Yike Bike for a few minutes, but I feel safer on the Segway. I'm too short for the Yike Bike's recommended 5'3" requirement. By contrast, my height is a non-issue on the Segway where I'm also more visible in traffic. I love how it handles the streets on NYC.
Distance/Battery Life. The Segway soars in this area. See specs on either site.
That said, I would (and may) still get a Yike Bike for the portability aspect. I just wish they made the seat adjustable. I'd have one today.