Well on the XT5000 if you had the old processor chip, Ram22 I think, the new FW gets rid of the stuttering you would hear when pressing buttons. On the XTS2500, the new FW allows you to access H/low power in the menu, & select which ever you want. With the old FW, a memory could only be set for hi, or low power, & there was no icon in the menu to change it. Many other improvements. These just come to mind now.