The KISS SPort has a very different design. Since the scrubber and counter lungs are set up to allow the air to flow into the scrubber twice before you breath it, if the scrubber goes out or the agent is used up, you have a real problem.
It is smaller, lighter (9 lbs with scrubber cover etc).
I have the regular KISS and like it a lot, I am not so sure I like the scrubber design on the Sport.
I am sure that we will have more comments soon. I had sent an email to Jetsam (Gordon) asking for information on the sport. I am waiting for someone to get one here so I can try and get them to let me test dive it.