I've grilled out plenty on both charcoal webers and my current gas grill.
I can't say I noticed a "flavor" difference either way. Once the gas grill is seasoned, it all seemed the same to me.
The only reason I chose to stick with gas is that it is way more convenient for me.
I rent. I have a grill I can wheel out of the garage and heat up very fast and cook on it, let it cool down for a few minutes and wheel it back in the garage where it is safe.
I couldn't do that with a charcoal grill.
I don't cook fancy-dancy stuff, I make hotdogs, brats, burgers, pork chops, steaks (few different cuts), salmon steaks, other fish and the usual potato/corn-on-the-cob/asparagus type veggies.
I don't remeber it tasting any better with charcoal.
I can tell you, you can mess up food quite easily on a charcoal grill. I can tell a novice griller right away with one bite of the "food". Brats a la Lighter Fluid...ug.
I don't think a novice griller can screw-up so easily using gas...