The "quick carb" is certainly faster and easier, but I wouldn't say it's always better. For one, force carbing quickly can often lead to a little more carbonic bite that takes some time to subside. So I'd argue that even though your beer might be carbed quickly, it still isn't ready to drink for a while after. Second, a lot of people use the quick carb method to carb up a beer very soon after it's done fermenting, which means less conditioning time for the beer, and possibly a less finished final product even though it's carbed and ready to drink.
Of course there are exceptions to every rule. If you brew the beer properly, give it enough time to condition, and then force carb and give it enough time to settle after that, nobody will know the difference. But if you're fermenting for 10 days, rushing it to the keg and force carbing so it's ready to drink in 3 days, you're certainly not doing your beer any favors.
So, like Kevin said, there can be good reasons to carb with sugar if you want. It allows you to keep the beer at room temp after it's already fermented and condition further while fermenting slowly if you already have other beers in the pipeline, etc.
You've got beer any way you slice it, so it's your process that will dictate how successful your carbing methods are.