Sort of, it is dissimilar redundancy though you would also have had to have a separate decompression tracking capability. The NERD would make it dissimilar redundancy where primary system is the solenoid/controller, and the backup is the NERD and leaky valve. The issue is in the intent of use of the system and the fact that there are still common components which doesn't make it truly redundant.
Is this all being incredibly pedantic? absolutely, but it's important to not the differences in what we are talking about.
Does any of this make the rebreather more or less reliable than any other unit to where it would be a purchasing decision? Obviously not since there is no one duplicating the thought process of the Revo *which would be incredibly easy to do in most rebreathers*, and to my knowledge there isn't anyone actively using the Revo for any exploration/expedition level diving. If it did make that big of a difference, we would all sell the units we are using and switch to it because it was a significant improvement in safety. If it is any improvement, it is marginal and does not offset the other drawbacks to the unit.
Look, if you gave me a Revo and said you have to use it as your primary backmount unit, I wouldn't complain. I wouldn't use it in its stock configuration because I think 5-cells is ludicrous, and I would bitch about it because it won't dive in flat trim in a wetsuit, but it's a perfectly suitable unit for 99% of the rebreather diving out there. Same thing that happens when I have to dive APD's, I would never choose the unit, but I have no issue when I have to dive it. If you're happy with your unit, that is literally all that matters. I take issue when people try to make their units out to be Gods gift to SCUBA when it isn't though. This thread devolved because someone brought up the superiority of 5-cells and how it's cheaper to use more of something than it is to use less of something *still curious about that logic, but whatever*, but if they came in and said that the Meg is superior to everything else because blah blah blah *I'd point out the PITA of the non-standard loop direction and the non-standard loop hoses combined with the awful latches* or the Fathom is the best thing since sliced bread and is flawless *point out that getting the head off when the weedwhacker line is swollen from salt water*, or the JJ *cave grit in the head, even with the shield*, etc. They're all flawed in their own ways and they all have design compromises made based on the designers priorities. This one just happened to be the Revo and for some reason that crowd tends to be the most vocal about their unit, probably because it is so different from anything else and they feel they need to justify it or they injected Paul's Koolaid with the fervor of new Fundies graduates from GUE.
