Personally, I don't like the looks for the Non-M BMWs (except for the Z4 Coupes. Those are just awesome in all trims.)
If I were buying a luxury car and the handling was HARDLY a difference between the two, it would be nothing I care about. I'm buying a luxury car, not a track car. I don't plan on doing 100 MPH through the canyons in my luxury car. If I was, I'd be upgrading the suspension anyway.
Nissan is FAR more reliable than BMW. Hands down. I've had a G35 and M35 and neither of them have been in the shop for anything other than oil changes. I've had the M for 3 years and had the G for 2 years.
Nissan wins in Value. You're not paying for the name BMW, and when the car goes out of warranty, the parts are cheaper than BMW's.
I think the BMW wins in Luxury. It's been a year or so since I've been in one, but I remember liking the creature comforts in the BMW more. Same options, but done very well in the BMW.
BMW's name comes with it's own class. I've heard girls say "I won't date a guy that doesn't drive a Bimmer." <-- Sad but true. Freaking hussies.
Curb appeal is a draw for me. I look at the two cars and I think the same thing about both of them. $50K car. Fit and finish. And both very refined.
BMW's going to get you laid, but you'll be happier with a better built car, unless you're just trying to get laid.
