They are both realistic, it is just a different lighting setup. In real life photography, photograher tends to use large lightbox above their shooting objects, to give a more even lighting. And that is where the sharp edge come in to view. Some photograher will adjust the lightbox position so that it will not be seen so obvious in the shot.
However, some reflections are needed on the glass, otherwise it will look like no glass on the car.
Remember...3D render can do things that real life can't. for example I can make a light plane to generate light only but not visible in the reflection by clicking an option to make the plane invisible to camera. But that is not real, you can't do that in real life. Just like in the old days where artist will airbrush out some harsh reflections that they don't want to see.
I have no problems with what renderer people use to render. But what is important is the lighting set up. Some I've seen are too dark which will need some light to bounce on the darkest area to obtain details of the car. But some are flooded with too much light and look like a 2D cartoon.
I've taken the reflection ring from the scene with the Suzuki GSXR and turned the output down to 1.7 and tested it with a car, it looks better on the car I tested it on than having the reflection plane above the car. I might need a combo of the 2 though.
the scene looks dark because you can't see trough the lights
first try to make that tutorial: http://www.cgarena.com/freestu ... rials/max/studiolighting/
then make different environment, and different position and angles for the lights it isn't hard, good luck! - just the answer for your pm, because i can't send it for you, for some reasons