2010 G37S sedan here - 81k miles.
Had it for 5 years, will probably keep for another 5. Pretty solid sport sedan.
-S-model suspension makes for a rougher ride. Know this if you are on the road for long stretches.
-S-model also has staggered wheel/tire size, so you can't rotate; therefore tires will wear faster.
-Normal wear & tear for me, mostly. Rear door lock actuators had to be replaced recently as they died about a year ago. Was tired of having manual rear door locks, so I got em fixed.
Stock Bose stereo is pretty solid. Car pairs better with Apple products versus Android.
It's been said before, but when Infiniti changed the G nameplate to Q, the old G37 body was kept and renamed Q40. They didnt sell real well against the new bodystyles, so you can get a low mileage Q40 for pretty reasonable prices these days. (mid-high teens) Just a thought.