Oh, hey, I was in this position.
I test drove both back to back a few times, so I'd like to think I have a pretty solid grip on both cars.
The Camaro is faster in a straight line and has the roar of the v8 which is just awesome. Honestly, that was almost enough to make me go with it. It also has back seats (although your kid will be uncomfortable back there, lol -- really isn't that much room) which may also sway your opinion, like you said. The handling isn't bad on the Camaro, but it is pretty typical for a car of its type.
What turned me off of the Camaro however was how mediocre the interior quality was. I had previously driven a Cobalt + a G5 (which is a Cobalt with Pontiac badging
) and with the exception of the "retro" feel, the interior felt the same. The seats were comfortable, but the materials felt tacky and just generally unpleasing. I wasn't a fan of the retro gages or steering wheel either.
I think it is worth noting that I am a young guy and wasn't in the market for a Porsche so my bar for interior quality wasn't really high -- and yet the Camaro -still- bothered me.
Also while the Z isn't as fast in a straight line, but it isn't that far off the mark considering a SS is made to go fast in the 1/4 mile. The handling in a Z makes up for that, too. Trust me. I've had the car for only a short time and I'm already in complete love.
Exterior wise the cars are a toss up -- that's all up to your personal opinion. I think that Camaro looks awesome, but the 370Z is just sexy. I am always smiling when I walk up to my car.
Ultimately it comes down to what you want and what you like, though. I strongly suggest you do some more research on both cars. Go to your local dealer and get a test drive in both and try to squeeze as much time out of them as you can.
One more thing -- while I agree on going and asking some Camaro dudes what they think, be ready for "BUY AMERICAN" and similar things. I read over a few forums and was extremely turned off by the community over there, but to each his own!
Good luck in your search and feel free to PM me if you have any questions about the car, I'll be glad to help!