Citroen used to make some fairly unusual cars, and they tended to get even more unusual the bigger they got. The old 2CV was a bit odd, but when compared to the big DS, it was the very picture of sanity. Compare either of these to the CX and well, you get the point. When Citroen first came out with the C6 we found the looks to be promisingly unusual. That is right up until we first saw it in person. Make no mistake, this car is pretty in photos, but it is just beautiful in person.
The lines of the bodywork clearly take cues from the old CX, but give an overall much cleaner profile. The short rear end, with the concave rear windshield, looks quite good too, although it does contribute to the annoyingly small trunk. The interior is fairly large, although here is where we start to get away from the classic Citroen. Apart from the places where badges are affixed, only the best trained eyes would be able to tell this interior apart from one of the German rivals. The same could be said while sitting in the car.
The seats aren't what you call uncomfortable but they aren't particularly special, especially when considering Citroens of old. While most European brands have spent the last few decades getting more comfortable, Citroen seems to be the only company moving in the opposite direction. Thankfully, this is no longer true once the car is moving. Nothing has a more comfortable ride, nothing. This is thanks to Citroen's famous Hydractive suspension system, which first saw service in the DS in 1955, and has been the envy of all other luxury carmakers ever since.
The C6 is not particularly fast, the only engine which is currently offered is a V6, and it's a diesel. It is a good diesel, developed by Ford, and it uses sequential turbocharging for a smooth application of power. It gets good fuel economy as well, particularly for a car of this size, and that's something. It just won't be giving an M5 or RS6 a run for their money. That doesn't seem to bother Citroen though, performance isn't the reason why you would buy this car anyway.
This is a car for people who prefer style and comfort over performance, and the C6 is certainly the class leader for both. Since this is a French car, the subject of reliability has to be touched on. In this category the C6 is, well, French. The electrical system in particular seems to be one of the few sources of misery for C6 owners. As a result of this, the car will depreciate pretty quickly, and if you buy one without a warranty then you can also expect some hefty repair bills.
You will stick out in an (overwhelmingly German) crowd though, and people will know that you place a high value on aesthetics and comfort. Moreover, you appreciate a little bit of healthy quirkiness.