Compare the difference in platform size between the PS500L (12" x 12.4" x 2.4") and the WS-Series 15" x 15" x 2.7" (h) x (w) x (d).

For many people the WS Series is a better choice, since the platform is larger and allows them to stand on the scale more comfortably or place oversized carton on the platform. 

The WS500L construction is more heavy duty with the entire scale weighing 22 pounds verse the PS500L only weighs 11 pounds.  For the $45 difference in price between the PS500L ($169.95) verses the WS500L ($214.95) we always recommend the WS500L over the PS500L.  Sure both units can weigh up to 500 lbs in 0.5 increments but the WS500L just does it better.  Since the WS500L has a bigger platform it distributes the load better over the scale.  Our analogy we be no different than a person pulling a camper with a 6 cylinder mini van verses another person pulling the same camper with a pickup truck with a large V-8 engine.  We all know the mini-van won't last long if you plan on towing a camper back and forth across the country for the next several years.  Read more here to help you decide what is best for you.