I have a KISS Sprit LTE which is basically the back mounted older sibling of the Sidewinder. Same basic parts, different configuration. I don't know about whatever "lies" these folks are talking about or the bashing of KISS's cold water performance might be. I can tell you a few things after doing well over 500 cold water dives on a KISS Sprit.
- The scrubber duration is about 4 hours. I routinely do 3 dives and runtime of 4 hours on my scrubber with no problems in 45-55F water.
- Water in the counter lungs is not a significant issue. If you somehow get enough in there to gurgle during the dive, just remove the lung and empty it. Recheck your pos/neg if you got that much water. I rarely see more than a few tablespoons worth in each lung after 4 hours.
- The exhale loop will also collect condensation, and your training should include how to quickly drain it after each dive.
My experience with KISS has been great since 2007 and well over 1000 dives on a couple of their units. Very few failures of resulting in missed dives. Maybe 5 or 6 times in a 1000 dives. Most of those were 1st stage failure, loop hose with a hole, user error let water into the BOV, and a leaky MAV that I too left too long between service intervals. Almost every other issue encountered could be addressed on the spot with basic tools and spares.
I've seen many friends with ECCR units experience far more failures on far fewer dives.
Don't be pushed away from the unit by internet anecdotes. Go ahead and try a few units and talk to people that dive them in person.