I remember flicking back and forth on the configurators when they were available online, the sports seats do have slightly bigger thigh and side bolsters compared to the comfort seats.
For me the big deal was that the Comfort seats can come with ventilation which the Sport seats can't - note that Comfort can come without ventilation as well.
For F12/13 owners - the Comfort seat headrest matches the rear seats. For F06 owners the Sport seat matches the rear seats. As a massive OCD sufferer, this was a big deal to me and one of the reasons why I got an F13
