Here in Miami, Canadians and others who come from places where waiters are actually paid a living wage often leave tips that the locals consider too small. In many of the snootier restaurants they have this custom of sticking a tip of 17 to 20% on each and every check. The cheaper restaurants never do this, just the ones where the wait staff already seems to do pretty well. They never add a paltry 10 or 15%, it's always more than the usual custom, which is around 15% for good service.
My policy is that if they tell me how much I have to tip, that is exactly what they will get...to the penny. Never a cent more.
I can say this, that in such places the service is almost always pretty good. Also, there are fewer smiley faces drawn on the check.
In other places, good service seems to be more dependent on management than decent tipping.