I originally liked the idea of a cooler looking sportier Prius not made by Toyota, but buying the Insight was a very bad decision. Sure, it was fairly easy to exceed the fuel economy ratings, but in return you get a very insubstantial car and in many ways a poorly designed car. Many things on this car had me wondering if anybody at Honda even tested it for more than an afternoon. It got to the point to where the battery would recalibrate and die unpredictably, leaving you wondering if you had enough power to pull out into traffic. I found the drivetrain very jerky and unrefined, especially when starting and stopping, and it often felt as though the wheels were driven by a rubber band.
It got the advertised mileage, looks cool, that's about it.
More power, smoother, less jerky transmission, more stable highway ride, better on-center steering feel, better interior materials, smoother ride, quiet the buzzy engine, more rear headroom, improve quality throughout, fix navigation POI search bug
I've found that the driveability issues which you've mentioned, e.g., acceleration, braking, shifting, came into alignment when I read about the Continually Variable Transmission (CVT), hybrid technology and regenerative braking. That little bit of reading (thanks www.insightcentral.net) helped me understand my car (2010 Insight EX-Navi) and learn to leverage it's fuel-sipping strong suits. I do agree that the CVT takes some getting used to, as you no longer have pep and pop that you get when you shif gears in an AT. But I've been able to fit right in with traffic, time the Auto-Stop well at lights and take off as needed. I hope that the forum listed above helps you find the same satisfaction in your Insight as I did.