How is Infiniti's all wheel drive system?
 

I've read online that it's actually in rear wheel drive mode all the time until the sensors sense some slippage and then it activates the front wheels.

Is it any good as BMW's x-drive or quattro?

thanks

I believe Infiniti is electronic AWD, whereas Audi Quattro is mechnical. In extreme conditions, Quattro is far superior. I have a G35x, in 5+ inches of snow, I can't drive faster than 120km without fear for my life. In my A4, in have no problems driving at 140km or faster.

That's exactly right! It's rear wheel drive until it needs more traction. I find it works wonders for me!... but my only reference point is an 06 Mazda 3 sedan, so I can't say I have a very objective point of view when rating THIS AWD systems performance. I like it though.

It starts in AWD, then after 12 mph, it switches over to RWD, and can transfer power to the front wheels up to 50% when it detects slip.

The system is fast enough that you'll never actually notice any slippage unless you're spinning 2+ tires; it takes about 3ms to react and transfer power.