Use it, but is it accurate?

I have used this app for over three years and have maintained a workout log. I recently switched from an iPhone to a galaxy 5 and ----whoa! The same routes I walked are now registering at about 25% less distance. What is up with that? Who is correct? If it is using GPS coordinates and a signal , why the difference? Anyone else seeing this besides me?

Ms B of about Sports Tracker for All Sports