The basin fill tools in Wilbur all share the same underlying code, meaning that they will always get the exact same results for the same input parameters. Having said that, the usual fill parameters (Slope = -1 to let the system calculate the slope value to use) won't get actual lakes in a geophysical sense, but will give a gently sloping flattish surface that makes it easier to get connectivity across lakes. Using Slope=0 will get you precisely the pit-filled image, but it gets tough to run rivers through the whole system because they stop when they lose a downward slope.