Both of these procedures use different forms of energy to destroy fat cells - liposelect uses ultrasound and smart lipo uses a neodynium-YAG laser. Once the cells are damaged, both techniques require standard liposuction to to remove damaged cells as well as additional fat. I do not know if any comparisons have been made about which method removes the most fat (nor do I think it very important). More important would be the skill and experience of the surgeon performing the procedure. The use of power assisted liposuction or traditional liposuction could produce equal results with a skilled expert.