Gas … for convenience, especially if you like to “sear” foods over a very hot fire with the ceramic infra-red burners. Quick to heat up, easy to clean, and easy to put up when done.
OTOH … charcoal seems better for “flavor” and slow roasting of larger items where they can be “smoked” a bit in the process. It’s a bit messier, and takes longer to get a fire going. I use a couple of Weber kettles when we’ve got a bigger feed going on, and they’re easy to manage the fire and control the heat. I use a charcoal chimney and an electric starter, or the chimney with a piece of newspaper crumpled in the bottom with some olive oil squirted on the paper. Usually have a very good bed of coal in 20 minutes, and I can save a lot of charcoal when finished cooking by closing the air vents on the kettle. The smaller coals also start up more easily on the next use to get a fire going sooner. But always a maintenance hog, with cleaning out the ashes and reassembling the kettle compared to high heat on the gas grill burning off the grill and the inside of the unit.
I wouldn’t be without both as they’re both useful and have their place …. but you should follow your priorities for the type of cooking vs convenience that you want to do.