The front bumper, fenders, and hood/headlights can be swapped as a set. You can get a Getta or Jolf with the swap. The interior is basically the same, same engine/tranny, it just comes down to - do you like a hatchback or a sedan?
The golf is the better seller in Europe, the jetta is a much better seller in the US. I have no problem with hatchbacks but people seem to think hatchback = economy car.