Yes. These cars are built rock solid - extremely reliable, you can beat the hell out of these cars and the motors love it. VQ37s are amazing engines. Only thing you need to check for are the clutch and slave cylinder. Make sure the clutch feels good, and that the fluid is the right color and there's plenty of it in the container. Take a nice test drive, get a solid feel for the clutch, make sure there's no play in it.
If you get a Z, get a 2011+ they come with oil coolers so you can run them hard and they won't pull power back, the oil temps will stay around the 200 area. I had to have an oil cooler fitted to my 2010 and it made an enormous difference.
My advice is definitely go for a 2011+ model of either car, you'll get the most reliability, newest updates, etc. Also, because you're buying used, don't skimp out on the technology package of either car. The Bose and Navigation are well worth it, the user interface is fantastic, easy to use, and it makes the interior of the Z look especially beautiful because it gives it a very complete look instead of the drab-looking base model with the cubby.