I've driven both quite a bit... the Z is def more agile and it's a bit smaller so a little lighter, all else equal it will handle better, the suspension is more stiff, more sporty where the g is more comfort, more luxury, more room and a bit heavier, hence not as good in handling... which is better for you depends on your priorities... the G is more of a sporty coupe where the z is a straight up sports car. reliabilty is about equal, they share the same DNA and are very similar in many aspects