I have owned my c4 coupe 1.6hdi (110) for almost a year. Its been almost trouble free. The cruise control was switching itself off after a few seconds. Not quite sure what was wrong, but Citroen fixed it no problems. Also, one thing to watch if you get a colour coded spoiler is the likelihood that resin will make the ends blister. I noticed this after 7 months, however, it was replaced without quibble. I absolutely love the car though and still think its the best around when you look at the cost to buy, the kit you get with it (I also had a few extras!!) the styling and in particular the sports seats which are extra comfy and the actual room in the cabin. In comparison I found the Astra to be very claustrophobic and cheap looking inside with seats that were not the best. The focus wasn't too hot on styling and I also found the cabin quite enclosed. However, at the end of the day its up to the individual what they want. As I said I love my car and I've had nothing, but good feedback from people who have commented, (plus, although it wasn't cheap I feel I've definitely had value for money in comparison with what I could have paid for either a Ford or a Vauxhall).
Another update from the owner, or rather the ex owner. I have taken the plunge. and exchanged it for an EGS model; an iron grey VTR+ 1.6HDI with panoramic roof.
It took a bit of getting used to the gearbox, but now that I have it's brill; fuel consumption is even better than the manual, getting well over 60 on a run and high fifties around town.
The only difference between the specs is that I had the security pack with the manual and miss the laminated glass etc, and factory fitted parking sensors. I asked for parking sensors to be fitted to the new car, these are after-market and not anywhere near as good as the manufacturers'; quite disappointing in performance. However, the car with the EGS can only be described as excellent.