Nothing really.
My Citroen dealer is absolutely crap. The after-sales manager told me that I didn't need an alarm as it had an immobiliser! They also told me not to remove/change the side badges, as they wouldn't know what spec the car was when they serviced it. I did anyway! They have also mucked about a few of my friends that have bought cars from them.
Overall - very, very poor.
I also had REALLY bad dealership problems with my Saxo. I went down for my car, and they hadn't put the wheels on. After waiting 30 minutes, they had to valet it, but the bloke had gone home and locked my car in the garage. We had to ring him and get him back to de-wax the car, and valet it properly. 3 hours after I went down, I got my car, and all Citroen did was buy me a can of Coke.