I have both, and use both. Contrary to what many think, neither is "better"; they're just different.
Smoke (charcoal) adds another flavor to food, but sometimes I might not want that flavor. There are times when I want to taste more of the meat and its spices, but with the unique flavor profile that comes from cooking over a flame. (I actually prefer my steaks seared on the gasser, rather than getting a smoke flavor over charcoal.) That's why I think there's a place for both.
Around here, we're under fire restrictions during the summer (no solid fuels allowed.) During that time I have to use the gasser exclusively. If I didn't have one, I wouldn't get any grilled or BBQd food — during the time of year when everyone expects it!
Even when I'm using a charcoal grill, I usually have a gas grill going. For instance, last night I was doing a Huli-Huli rotisserie chicken. While it was cooking on the kettle, I was using one of the gas grills (a Broilmaster) to cook up some cauliflower steaks. Even if I don't actually cook on it, I'll have a gas grill set up with one burner on low and a Pyrex baking dish on the rack. The dish stays warm but not hot, which gives me a place to put food coming off the grill without it getting cold or cooking more. When I'm cooking in the middle of winter, that's important.
Gas and charcoal are complementary; I honestly wouldn't want to be without either.