It's obvious that drifting around turns gets you speed boosts that can make a big difference a lot of the time.
But often, when trying to keep a drift going - especially to get to the 3rd level in MK8D - it means I'm cutting corners less tightly, releasing the boost when I'm not facing dead center, etc.
I know it depends on the scenario, but as a rule of thumb, is it better to optimize for max drift at the expense of the tightest path, or should you basically drift as best you can only to the extent that it doesn't cause wider turns, etc.