BMW just has some good competition now. =) The Infiniti is a great car.. entry-luxury just like the 3er... Sport Luxury if you will. The Infiniti is on a great platform, has a very sturdy and proven engine, great suspension setup, and pretty good looks. I was looking at them way before I even considered getting a 3er. The thing is.... when I drove the BMW there was no contest. I liked the steering input and other driving feel over the G35. I also felt that the interior was a few points above the G35. The leather is a bit more comfy, better use of wood, and almost exclusively soft-touch plastics(which the G35 has little if any inside).
It's really going to come down to personal preference on that one... They're close enough in price to be shopping buddies(4-7k difference). If I had one I wouldn't be complaining.