Had one of these as a courtesy car whilst my 370z was being serviced at Infiniti. Thought I'd post up what I thought of it compared to the 370z, drove it for about 120 miles albeit mostly motorway.
Driving wise, it had the same auto gearbox that's in the 370z, with flappy paddles on the steering wheel if you switch it to the DS mode. It worked well and I quite enjoyed going up through the gears, but for me a manual gearbox is far superior and more fun to drive. It didn't feel anywhere near as quick as the 370, but it definitely shifted! Was a much more smoother ride too and was extremely comfortable. Suspension was pretty stiff too so it cornered pretty well.
Inside it's loaded with all the goodies my 370 has, connect premium with the hard drive, BOSE sound system and Bluetooth audio. The interior is slightly more classy than the Nissan, as you'd expect from the Infiniti range. The roof could also go down, even though it's a hard top, but I didn't fancy testing that out in December. One thing it did have extra the 370z doesn't was the reversing camera. This was really handy and I plan on fitting one to mine tomorrow having bought all the necessary hardware for doing it.
Looks wise, the car is lovely on the inside and fairly nice looking at it from the outside. Albeit a different car as it has 4 seats, I don't think it's half as nice as the 370z or the 350z for that matter. I don't know why, but it reminded me of an Astra or a focus convertible, and that can't be a good thing!
All in all, I certainly wouldn't be rushing out and buying one. It's a bit too grown up for me and is a lot more refined and subtle than the 350Z and certainly the 370Z.