It's great to hear 7AT Z owners are happy with the auto transmission. I bought a 7AT G37 back in 2009 and what I experienced with the transmission was not satisfied.
During the first couple of thousand miles, there was a rough 4-3 downshift that happened around 30-20mph. It was fixed with a software flash about a year later. But it also introduced a new problem: downshift hesitation. It's best to describe with an example: if you go around 50mph and brake to around 35mph, then start to speed to again, there comes a huge hesitation for like 1 second, then the car starts picking up and accelerates like a rocket
On the top of that (1) the trans seemed to be confused in traffic, not know what gear to pick, (2) Transmission flare (upshift from 3-4, the rpm jumps up like 500). So Nissan came up with another flash (2nd) a year later, things got a little better but still not as great as the 5AT. The 2nd flash also caused the acceleration to be linear (more smooth and less sporty).
It's not just me. The problems have been documented well on myG37 forum. There is a huge thread that's still going. But from what I've heard, Nissan has finally worked all the bugs out with 2012 year model. I hope it's true.
By the way, that's how I wind up here with a 6MT 370Z
