Introduced in 1989 in North America, Infiniti is the luxury division of Nissan.
Their cars take off from where the Nissan Maxima and the Z cars leave off. In spite of this, the high end Nissans and Infiniti's share some of the same engine packages. The early years of Infiniti left something to be desired, especially in the styling department with many of their cars looking between nondescript and ugly.
Around the 2000 model year Infiniti almost folded due to soft sales in the luxury car market and Japanese economic conditions. Fortunately they hung in there and turned things around, for the modern Infiniti's of all models are a thrill to drive, and the styling department came up with some great looking vehicles.
There is a varied line up of vehicles from small sports cars, luxury sedans and futuristic looking SUVs. While 4 cylinder engines were once available, all current models use V6 and V8 engines, some with some very impressive horsepower ratings. There is a hybrid package available and also a diesel V6 but only for the European market.
As for problems and concerns Infiniti's are generally very reliable.
However, there are a few things that I find irritating. One in particular is that the valve cover gaskets are part of the valve cover. This makes for a very expensive valve cover gasket job, and unfortunately they fail frequently. That being said, there are few other problems with the cars.