No car is a good investment. I've owned various marques and the one that has stung me the most so far has been Mercedes. I've found that if you move around makes such as Saab and Volvo, and play them off a little as you negotiate your new car, they give you far better trade in deals than the other premium brands. I've never owned a Citroen. The C6 has really captivated me so in the end I'll probably let my heart rule my head and opt for this car.