The 1990 STS continues Cadillac's commitment to excellence. Yet it departs from the "old-fogie" connotation of the Cadillac name. It has a spacious and comfortable interior, along with a sporty design on the outside. It drives very smoothly, and handles well. My car just turned 170,000 miles, and is still running strong. This is testament to the value of preventative maintnance, and the quality in manufacturing of Cadillac and GM automobiles.
The on-board computer quickly notifies the driver of a problem, and nags him to fix it (very effective). It saves time by computing the average mpg ratio automatically, and sensing the life of the engine's oil, among numerous other things.
The only real complaint I have about this car is the gas mileage. The pre-Northstar era engine guzzles gas in the city, and only accepts premium grade fuel. This becomes expensive very quickly.