I have been using Dalia's service for almost 3 years and I have no complaints, only praises. I have called them on numerous occasions as late as 1am to confirm early morning pickups and they always answer the phone. One time they called ME at 4am to let me know that my 630am flight was delayed an hour to see if I wanted a later pick-up! Over the last few years I have gotten to know them personally and I couldn't imagine using anyone else. The cars are always clean, the ride is always smooth and the drivers are always on time. Also, their prices are very reasonable.
Pros: Personal service, reliability, clean and new cars.
Cons: I wish they owned airplanes as well!