TG, only you can say which one you like more. You can’t go wrong with either.
If you’re afraid of the repair bills, you might want to consider the fact that with a G37, you can bring your car to get it serviced at a Nissan dealer. You’ll save on the repair bill but you won’t get the pampered treatment. I can’t speak for BMW, but for Infiniti, you can buy your own parts and they’ll install it for you and only charge labor. I know Mercedes won’t do it, but I’m not sure about BMW. This will allow you to save some more $ on repair when the time comes. Buying parts online will always be cheaper.