aside from some perceived unit-bashing, I think in general there are some good points being made here, which are the roots of the never-ending design discussion...
1. that there is very little 'truly new' out there. While not clones of existing units per se, a rebreather is a rebreather is a rebreather for the most part, and the differences often times break down to build quality and configuration more than anything (with the exception of proprietary electronics, and truly new scrubber design features like the Boris)
2. that there is not, but perhaps should be an industry standard (backed with some research) for gas injection/flow through the loop to avoid any confusion from unit to unit
3. there is no such thing as the perfect rebreather because they are all intended to be mission-specific which is usually a reflection of designers' past experiences, so as we continue to see 'mix and match' "new units" (which they are not necessarily) from the homebuilders (myself included) there will forever be debates on what and why....our community and the rebreather market is WAY to small to accomodate so many small mfg's and arrive at any industry-wide accepted 'perfect unit'
4. this is all of course part of the fun in being in this little world
