The Sports edition is touted to be better fitting and more comfortable. It moves around less due to it's brad mod (thingie which hooks under the left arm across the chest).
Reviews that I've read, people who both owned the RS7 and the RS-sports chose the sports over the RS7. The only thing you might lose out would be the handphone modules and all that.
(I'm not using one, would love to have, if not for me being more of a tripod-guy too.)
well, thing is, i don't fancy sth underneath my arms, especially when i am sweating=P