Honestly the Genesis is not a bad car. We have 2. One is gonna be supercharged Street/Modified class and the other will be twin turbo unlimited class.
As for comparing the two, the 370z do have some major advantages over the genesis.
The tranny is better, Engine is better built, and the response in the 370z is superior.
However with some aftermarket parts and tuning, the Genesis can be a very strong competitor.