i guess i'm not seeing why walker is better than a grasshopper...
Walker, 7 MPH
Grasshopper, 10 MPH
Walker, 12.4 Cu. Ft.
Grasshopper, 15 Cu. Ft.
Walker, 4.7 Gallons
Grasshopper, 8 Gallons
attachments are about the same although walker may have a slight advantage, for me at least...i like their aerator over grasshoppers, and their bed edger, and their snow blowers, grasshopper is 48" and 60", almost too big for sidewalks, walker gives you a better selection, although on driveways a 60" would the better choice...
all in all though i can't see why a walker is "better," the numbers are significantly lower than grasshopper...