I also enjoy the comfort and convenience of a limo/van service. However, if you decide to use such a company, I suggest that you call, call again and call yet again to confirm. My experience has been that different agents from the same company will tell you different things when you call to make reservations. This includes conflicting information about rates, car seat and seat belt availability, the number of people that a limo or van can comfortably hold with luggage, whether the internet coupon can be applied to your trip, etc. I've also had a limo company show up at the wrong place at the airport, and then show up very late at the port without the car seats that we had confirmed (the driver fessed up that he was late because a police officer stopped him to give him a speeding ticket - yikes!). We did not let any of these experiences bother us or ruin our trips, but they have taught me to be as diligent as possible when confirming our transportation plans. Even then, you can only hope that all goes as planned.
I hope you enjoy your trip!!!!