Have owned my C5 Exclusive for just on 5 years now and 140000 kms later I can honestly say that the whole ownership experience has been mostly delightful. The car still feel and drives like it did from new, is supremely comfortable and exquisitely good on fuel.
My car gets mostly freeway and country driving and regularly returns 5.5-6 l/100...terrific on interstate runs...(It's done WA-EAST many times! 12 hour driving days and one still feels fresh!)...the love continues. ...even after 5 years!
From a comfort perspective the cabin is so quiet that a very long days drive is really easy. There are some 9 different adjustments on the front seats so staying comfy isn't difficult. The climate control works a treat though it needs to since there is a lot of glass.
The leather seats are much firmer than any Citroën I've owned in the past but are still super supportive and are heated too for cold mornings!
Carrying capacities are fantastic. ...it has a big boot and with the seats folded down can swallow a bicycle and a load of other big stuff.
I've managed to sleep comfortably in the back of this car on camping trips and I'm 6 foot tall! Of anything negative about the car....it does lack rear leg room...and is really not comfy with 3 adults across the back....two though will find it luxurious as long as they aren't too tall!
Other failings? The dealer backup. ...my car has been brilliant in the reliability stakes but earlier on it developed a range of electrical glitches (all related!) that took ages to get sorted....was the only negative part of the whole ownershp experience. ...