The best aspect of the car is its styling. It is timeless. It looks as good today as it did on the show floor in 1975.
It is a good touring car even though luggage space is minimal. Also, don't put chocolate or deodorant in the trunk - it will melt!
And speaking of melting, the cabin gets extremely hot while driving!!! This is due in part to the poor ventilation and A/C system, the intrusion of heat from the cooling system, and the greenhouse effect of the front window. In later 308's, a vent in the hood expelled cooling heat from the radiator. I understand it helps.
Finding 205/60-14 series tires is tough today. The Yokohama A321's fit nicely. However, for better handling, one should find 16-inch Ferrari wheels that enable lower profile tires.
Hard cornering starves the fuel bowls due to their orientation in the car. This leads to a stutter in acceleration around a corner.
Expect about 12-15 MPG in town and 18-20 MPG on the highway with premium unleaded gas.
A major service (belts, plugs, fluids, valves, timing, carb cleaning) should be performed every 10K miles or 5 years. This will run $1,500 to $2,500 dollars. Much of this labor can be performed by a competent hobbiest mechanic.
More so than any other exotic (excluding Porsches), the 308 is easily maintainable, parts are readily available and cheap, and it is the most recognizable car on the planet.