I couldn't really comment on your first question, as only have a tiny bit of experience with a Halcyon rig and none of the others you listed. But your re-phrased question I can respond to
[Warning: I see I got very wordy and there really didn't seem to be any "smilies" that lent themselves to breaking it up. Please feel free to just skip on past if you just wanted a few sentence summary :blush:]
My first bp/w experience was with a rented Halcyon Eclipse rig with the standard sized plate. Halcyon make regular and small plates, and for my build, if I bought one, it would be the small sized plate (I don't know what size you are). In general, I liked the rig and the quality seemed very good. It was my first bp/w experience and -- even with the "wrong" sized plate -- it fit me so much better than any of the vest BC's I had tried that it was amazing. I really liked the webbing. I know that's a small detail, but for me it was the perfect combination of stiff but still comfortable to handle. For my diving (warm water single tank), I thought I might like a smaller wing (both in # of lift and in width).
Since I had not bought a Halcyon rig on that trip (they were not able to get the small plate in while I was there), I checked out some other ones to compare. I needed a short plate, so that ruled out many brands because quite a few only make one size.
I decided to buy a DSS rig for several reasons:
1) A large range of plate sizes, of which the small looked like it would fit me well (it does). Also I thought the angled shoulder strap slots looked like a good idea (minor point, but still). I couldn't tell this from the web photos, but the metal is very nicely machined and detailed. Nothing sharp, sloppy, or objectionable in any way. There are plastic/rubber type inserts in the webbing slots. These make it a bit more difficult to slide the webbing around (say if you change adjustments for a thicker wetsuit); but on the other hand you don't need any sort of keepers to keep it from moving.
2) A tidy wing (17# and narrow) with a nice short inflator hose (of course they can be changed).
3) A nice system wherein you can very quickly and easily separate the wing from the plate (my wing never ended up under a metal plate or other "dangerous" stuff in my dive bag, and rinsing it is a breeze since it is not attached to anything and there is no temptation to be lazy and not separate it).
4) I felt that DSS' quality control and engineering would be excellent (no complaints).
I now also have an Oxycheq 18# wing. I hesitated to buy this because Oxycheq's customer service does not inspire confidence, and I usually like to vote with my $. But, it was the only other narrow/small wing I found, and I wanted to try one with the inflator elbow off to the side (I doubt this would be a problem for anyone else, but I am very short waisted and the DSS wing elbow would tend to lodge between my head and my specific reg, even with various tweaks). I will say that I think the quality of the DSS wing is much better. Not that the Oxycheq looks like it will fall apart or anything, but just small details (and I like details).
For example, the DSS fabric is more supple, and it packs down nice and flat when empty (paradoxically, it also seems very tough). The Oxy wing stays kind of "puffy." Also, the DSS wing has inset mesh fabric right at the bottom of the wing to drain water. The Oxy wing has brass grommets (can corrode and mine show some wear) and they are close to the bottom of the wing but not right on it, so water does not drain as well. The "stiffer" wing fabric showed some wear where my tank touched it after the same number of dives on the DSS wing did not. The Oxy wing comes with an inflator hose that I would find too long (but I bought it from Scubatoys and asked them to put a short one on and they did, so it is the same length now as the stock DSS one). The Oxy wing does have a zipper so I can get into it to clean around and potentially patch the wing; but I still much prefer the DSS construction overall (probably less likely to need a patch since I can keep it away from my plate in my dive bag).
One last comment on the wing: DSS does make quite a few different shapes and sizes of wing. I think that the horseshoe shaped one might also have worked for me, as it looks like it has a bit less of a "peak" above the top locator. But again, I think I'm pretty atypical (shorter, female), and the wing would probably fit most people just great. So don't take that as knock on the gear.
Both the Oxy wing and the DSS wing have provision to keep the tank in place without an STA. They both worked fine as far as I could tell, but I liked the DSS one better.
The DSS plate has a shallower bend than many others. I think for most people this would be an advantage (tank closer to your back for less rolly turtle effect). I ended up feeling like I wanted the tank a little further from my back, but again, I think this is only because I am far from "average" build. I also wanted to be able to lower my tank a bit more (even though the DSS slots enabled me to lower it more than any other plate, to give it credit). So I bought an Agir-Brokk STA, which has three cam band slots. This made it all fit really well, so now I have a bit of a hybrid. One plus I could see with the plates that have a higher bend is that you can store an SMB in a pouch in the bend (between the plate and your back). I think that might be nice.
If someone now gave me "mad money" and said I had to spend it on bp/w related gear only, I think I would get a DSS Kydex plate to go along with my DSS stainless one, and a DSS horseshoe shaped wing. If there was money left over, maybe a roll of Halcyon harness webbing (I would have to check it out again to see if I'm remembering it more special than it really is).
Blue Sparkle
