Some ideas about hiring a Limousines - found on the web:

What Limousine Company to choose.
There are a number of questions you should ask yourself before choosing a Limousine Company and Chauffeur. These include what kind of impact you’re looking to make, and what level of luxury you are after? At a more practical level, you’ll need to decide what services are available in your area, how long the company has been in business (and thus their level of expertise) and what the certification and guarantees that they offer to ensure you get the service you hired. A list of previous clients usually gives a good indication of the level of the company. But there might be a problem finding out some of the information because of discretion. In general, have a look at the web site and see if you can find testimonials.

Vehicle Type
In the general, the preferred choice for a limousine with chauffeur include Mercedes-Benz, Rolls Royce, BMW, Chrysler and Bentley: the well-known brands offer all their uniqueness, style, opulence and class. You may even be able to choose the colour of the Limousine, silver, dark blue or dark green etc.

Chauffeur
The ideal choice for a limousine with chauffeur is a company that provides chauffeurs to meet your particular tastes. You can, for example, have the ability to specify what the chauffeur  wears, whether to wear a shirt with a neck tie or open and a suit etc. Chauffeurs can meet additional safety requirements, hiring former law enforcement personnel of the army or police, for the close protection or the protection of VIPs.

Charges
Hire of chauffeur will depend on whether you are looking for airport transfers, or a current account with the ability to benefit from concierge services. In all cases, you must ensure that the company you choose has no additional hidden charges that you are unaware, as mileage rates or implicit service charges and passenger fees. Most services will be charged for the high holidays, and these kinds of things should be clear from the beginning.

Additional options and concierge services
Some companies provide benefits for the occasional use of luxury vehicles, such as wedding guests or persons on a stag or hen night, and include things like champagne, balloons and bowties. Others offer the life-style catering services for a customer demanding a real taste of luxury on an ad hoc basis. Concierge services may include hotel and restaurant reservations, theater tickets and theater, flower delivery, personal shopping, office and residential, private aviation services and much more.

Baggage Services
Some limousine companies also offer chauffeur services for luggage transfers between airports and transportation for other items to be shipped elsewhere. For high-paying customers, which makes all the difference to be spared the inconvenience of waiting and baggage carousels in commercial airports.