The debate whether the charcoal grilling method is superior to gas grilling has waged since the 1950's. Charcoal grilling can be time consuming and messy. But most grilling hobbyist will swear by the charcoal grill. The gas grill has it's followers but those from both groups believe that numbers show that the average weekend warrior buys the gas grill for convenience.
The gas grill has the advantage of easy start up. This means that the time required to produce grilled items can be significantly less. It also has the advantage of being easier to control heat and control the cooking proccess because of having knobs to control the heat and therefore a more even cooking surface. Another big advantage is the mess is much less and that translates into quicker cleaning times.
There are some advantages to the charcoal grill. The charcoal grill burns much hotter and provides a flavor that the gas grill can't match. The gas grill can offset this somewhat by using a smoker box. Another advantage to the charcoal grill is that it lends itself to a certain interactivity that many find appealing. There is someting primal and yet soothing about "manning the grill". The amount of time that one stands over the grill lovingly tending to the grilled fare is somehow satisfying.
In the final analysis, I think that the grill method that you choose will often times reflect what is most important to that person. If you are someone who puts a premium on time , then the gas grill is the way to go. If however time is not the major priority and you are looking for an unhurried and laid back approach that yields the most flavorful results, the charcoal grill is the way to go.