I have a G37x (for my wife) and a 328 xdrive coupe.* Both 2011s.
G37 os OK. Great acceleration but very nose heavy. I would be scared sh!tless to push that thing in a tight turn like I push the coupe. The AWD system is pretty stable.
However, there are things that are just inferior to the BMW:
-On long drives it is a little less comfortable. The seats are a little too short.
-When you really hit the gas (floored) the whole car buzzes. But it takes off like a rocket too.
-The nav doesn't give you traffic issues as clearly or quickly.
-The heat is always too hot and the AC too cold. With the BMW, I set it on 68 when I sign the lease and that's the last I ever do to it.
-The stock tires
were bald at 25k.
-I forgot what a PITA 3k oil change interval is.
-Gas mileage blowwwws. 20 MPG if you're lucky.
However, if you're leasing Infiniti is really competitive. I am paying 30% less for the G and both cars are similarly optioned.
*I know -- someone is going to say "Why didn't you marry the BMW?"