The Oxy is a nice little rig, although I'm not fond of the way he set up the shoulder straps. All the "comfort" harnesses have a split upper shoulder piece, but the Oxy's is a definite split. Not that the Ballistc Nylon that holds the two pieces together would ever fail, but it's still not webbing connected to webbing. Although the way he did it makes it sure fit nice.
The DSS rig is nice looking. I'm not too keen on the velcro in the shoulder straps (as Tobin and I have already discussed in length on another thread), but as long as you're not tearing it apart and putting it back together all the time, that shouldn't be an issue. Other than that, my only other real comment on the DSS rig is that I like rounded d-rings better, but that's a personal preference. Maybe it's this irrational fear I have of getting things caught under my fingernails....and I know, I'm wearing gloves most of the time. That's what makes it irrational.
Another setup to look at is the OMS comfort harness, although it has it's downsides, too. Lots of padding, which in my opinion just makes for a bulky shoulder area. Could be slimmed down a lot. Solid setup, though. Might be more pricey than the other two, though. I myself am getting their deluxe harness (hog with one shoulder clip) which I'll thread like a hog harness (no neck crossing for me).
As for the scary knife in the rescue thing....that's what shears are for. Of course, you should always have complete faith in your buddy, too, right? Even if they are weiding their "Scuba Sword" near your soft parts?