I have to say that I'm in love with the new XF line from Skechers! I already own a pair of "regular" Skechers Shape-Ups and I really wanted something lower to wear while jogging on my treadmill. I decided to give the Accelerators a try and I am so happy that I did -- they are awesome! The kinetic wedge seems to be a different material than the kinetic wedge in my regular Shape-Ups. I don't know how to describe it other than it's more of a smooth, shiny rubber and seems to be more durable than the original kinetic wedge. I have the light blue/silver Accelerators, but I like them so much that I'm going to purchase the black version. Another thing that I really like about these shoes is the mesh paneling. My feet don't get as hot in them. I've also noticed that the insole is different from the original Shape-Ups. It's a smooth material and has more perforated holes for breathablity. I'm so pleased with these shoes that I won't go back to the original Shape-Ups. These are fantastic for athletic activity and definitely more stable. FYI -- I've found that these shoes run true to size. Enjoy!