We engaged in a year long comparative test on behalf of a company I do independent product evaluation for, soley to determin a proper answer to that question. Two identical test buggies, one ported, one not. Unfortunately the long and short of it is, sometimes it helps (carries less snow, less wind drag) sometimes it makes no difference, and sometimes it hurt (carries more snow, decrease flotation and allows the track to create an approch wave before upper rear idler). For the record, I quit using ported tracks on any of my builds.
