I'm not saying that Infinitis aren't reliable, but I don't believe that Nissan/Infiniti has reached the level of reliability that Toyota/Lexus and Honda/Acura have. First of all, J.D. Power is hardly the only arbiter of reliability, and even they show that Nissans are much less reliable than the others.
Also, since someone brought up the J.D Power rankings, let me mention this: their "long-term" reliability ratings are based on the number of "problems" in three-year-old cars. I am not particularly convinced that how well a car holds up for three years is highly predictive of its long-term reliability. Just as importantly, how useful are these rankings if they don't discriminate between different types of problems based on severity? For example, BMW's rating is not much worse than Toyota's...but if 60% of the "problems" with BMWs are serious engine problems, and 60% of the Toyota "problems" are, say, hatch rattles, it's obvious that J.D. Power's "long-term reliability ratings" don't mean much.
Just my two cents on the subject. Sorry for the hijack.