Note: I just leased my new Jetta a week ago today.
I test drove quite a few cars before deciding on the 2000 Jetta GL....the Honda Civic, the Jeep Cherokee, and the base Saturn model (the SL?) among them. They were all very good cars, mechanically solid with a smooth ride, affordable even with some essential extras, and dependable.
So why the Jetta? Basically, it came down to the design and the feeling that design gives the occupants of the car (especially the driver). The Jetta has that solid yet elegant industrial feel to it...the design of the interior and exterior of the other cars seemed cookie-cutter in comparison. The Jetta interior and exterior convey a sense of reliability, adventure, cleanliness, stability, and even excitement all rolled into one.