Wow - my experience has been different from most here.
My wife and I both own 5 year old cars which were both purchased new - both cars have about 75k miles
Wife - Infiniti QX56 (which I believe is now the 80) - biggest POS I've ever owned. Car is in the shop consistently. Tons of problems throughout our ownership. Every suburban mom in my area drives it - lots of problems
Me - Audi S5 Cabriolet - my favorite, most reliable car I've ever owned. Never had a single problem.
My infiniti experience has been so bad I would never consider buying a car from them again.