I've found my C5 to be great for motorway cruising, which is all I do in it - it is comfortable & refined.
Performance is OK & fuel economy is great - though it does fall off quickly if you get much above 70. I can average 55 mpg if I keep a bit under 70mph.
- Dirt cheap to buy for a modern diesel.
- Reliable - never broken down during 40K miles & car was 5 years old when I got it.
- Huge load lugger.
- Automatic lights.
- Automatic wipers.
- Comfortable seats, like the armrest!
Cup holders are rubbish.
Climate control is a total waste of time - you always have to adjust the temperature, which kinda defeats the object. Dual zones is nice though, & works well.
Seat belts soon give up, & don't wind in again.
No rear wiper??!
Light bulbs are a nightmare to change, & blow more often, cos auto lights are always turning on & off.
Stereo is decidedly average.
It is big & unwieldy around town - diesel engine is a bit 'all or nothing' in low gears.
Electronics are an annoyance - it's always flashing up warnings for things which are just fine, including oil level, airbag, washers etc... you just learn to ignore the stupid thing, & it shuts up eventually.
The interior trim is rubbish - but you can replace worn trim cheaply enough from Citroen. I've replaced the gear stick & 2 internal door handles, which were peeling rubber off (nasty).