It depends on your profile...
For bounce you make a path that is basically a line that doesn't need to connect on the ends. The disadvantage is that your going to be covering the same area you just covered when you get to the ends of the line. This might be useful for say in a cave or an instance when the path back out basically is the path in.
For circle you have to make your path connect at the end points. This will create a big loop. No real disadvantages
So it really depends on the situation, but for the most part I think people use the Circle method.