I have an early build Z, Nov 2008. And aside from a constant rattle from the rear somewhere I haven't had a single issue. No stuck hatch, no ECU noise, no overheating and no paint problems. I do have a clunky 1-2 shift, but nothing terrible. Overall I am very pleased with the car.
As was already pointed out these message boards are a blessing and a curse, what can be a large problem with very few cars gets talked about, A LOT and it can appear that the problems are more widespread than they really are. The few people that have had legitimate issues seem to have been taken care of by Nissan under the warranty that we all get.