I'm splitting my answer to this from the original thread. I was originally going to post this in the DIR forum but I thought maybe the general tech diving community would like to hear of our experience.
In 1999 I started following the DIR path and many of my buddies did as well. We were happy in our DIR-ness. In addition to our local dives, we were able to regularly pull off some small expedtions to the West Coast of Canada and the Great Lakes and some very large expeditions to the Eastern shores of Canada with trips to Nova Scotia. All very DIR and all very OC. For our Nova Scotia trips we would each ship out approximately 500 lbs of personal gear plus team gear (compressors, boosters, etc) and we would bring in anywhere from 20-35 T's of Helium and 15 to 20 T's of O2. Lots of gas.
We knew about CC technology as one of the leaders of our group (Greg Mossfeldt) had extensive experience with rebreathers in the past but had switched back to OC diving. We knew the benefits of CC but we were more comfortable with the tradeoff of the time limitations of OC vs not knowing what was in every breath we took. Among other things.
In our 2003 trip to Halifax we found the wreck of the Athelviking (google it for details). She lies in 310' we had done a few dives on her but we noticed that the logistics to do a dive like that on OC were getting a bit crazy. More stages, more deco cylinders, etc, etc.
After our trip in 2006 we realized that we were starting to ride the ragged edge of what we were comfortable doing on OC. And we were concerned since some of the future targets we had in mind were in the 325-350 range. Our choices were to scale back or change diving practices. So we started looking at CC. The decision of Mike Barnette and the AUE divers to go CC also made us step back and go hmmm.
We had in mind what we wanted if we decided to go CC. The fewer electronics the better. That ruled out all electronically controlled CCRS (Prism, YBOD, etc). So that put us into either the SCR offering from Halcyon or the mCCRs (yes we know about the depth limitations of mCCrs. We've found workarounds.) So our short list was the Halcyon, Meg Copis or the KISS.
Out of curiosity Greg had bought a KISS classic in the spring of 2006 and was diving that intermittantly so we were watching his progress with interest. We initially looked at the Halcyon because as DIR divers it addressed a lot of of our concerns with closed circuit technology. However we saw some Halcyons in action and we really felt that they while they do well in the cave environment, they wouldn't be appropriate for our dives (OK, OK, I'll fess up, we thought they were too flimsy to stand up to boat diving in an open ocean environment).
We looked at the Meg Copis but we ruled that out as we didn't like the over the shoulder counterlungs and the clutter up front and that the work of breathing issues between OTS and back mounted was minimal. So that left us with the KISS classic...until this past spring.
I had heard about the rEvo RB around February of this year from my friend and KISS owner Peter Piemonte. Talking to Peter it sounded very promising and he had just bought a rEvo. I then mentioned the rEvo to Greg. As it turns out he was going to Seattle to do some more instructor type training on his KISS with Mel Clark. While he was there one of the other students was on a rEvo. Greg was so impressed with the unit he bought one (being single, he can do that sort of thing). And so the rEvolution was on.
Now this all happened this past spring and summer. Also in that time period my Helium price quadrupled. But I still wasn't sold on CC. I saw too many problems in it that I wasn't comfortable with. So I had to make a decision. Deep OC was becoming just too expensive and too unwieldy to do in order to reach our goals. Do I give up the deep game and become a pretty fishies Coz diver or make the move to CC? Or sell it all and go kayaking?
In September I was with a group from New England diving the Halifax wrecks. On one of our weather days, I had a chance for an excellent talk with Peter about CC, go over the KISS and rEvo in detail, and have some concerns of mine addressed. I also had a chance to dive the KISS (I was told I lost my DIR halo then). And being in Halifax I realized that I wasn't willing to give up my deep diving goals yet.
Peter had his KISS for sale at a very reasonable price and I made the jump last month. Most of the others that I dive with bought KISSes as they started on the CC path earlier in the year. Half of those have now switched to rEvos. The people just making the OC to CC transition are buying rEvos.
This decision was not made lightly or hastily. For myself it's been at least 2 years of intense study and navel gazing to decide if this is something I want to do and if so, then which direction. I'm looking forward to this new chapter in my diving career. CC still scares the crap out of me but I suppose that's better than being nonchalant about the switch. I now have my KISS Classic #133 all ready to go and have been known to stroke it lovingly. My wife will not allow it to come to bed with me however.
