I was under the impression that the benefits are more about they don't unload like coilovers and more stability?
Just like when you run coilovers with bypasses often times they remove the dampening or run a much smaller coilover and let the bypass do the dampening work in this case it would be an Ori strut and just using it for his dynamic spring capabilities
You actually tune the unloading aspect with them. You could drop a tire of a ledge and the rig will level itself back out 2-3 seconds later, not that one wants that but that's what you're tuning around. It took a bit of effort to get a buddy's rig to drop a tire and level out fairly equal and quick. I can't imagine the effort to make response times fast enough for a competitive racer but I could be wrong.
While you could go fast in them long term speed may become an issue with heat buildup. Ori's had that issue early on and fixed it with the external res. But I've yet to read how far that allowed them to be pushed and for how long. I would personally call them the best air shock available and a better option than a cheap coilover but I personally wouldn't throw them into a ring with kings and bypasses.
They do have a 1,900lb weight capacity so I'd assume the lower you come to that weight the more you'd be able to get away with.
You mentioned an all around rig you're building, I'm in the process of collecting parts to do the same (axles are all that's left) and I'll be using 16" ori's on all 4 corners, 4link. You could go fast with them so if you're not racing all day you'll be fine. They make quick work of setting up, they are compact and put on paper you don't need to buy sway bars, bumps, or limiting straps so the cost of them truly isn't all that bad.
You could run duals on each corner and tune them to work together and probably be fine but at 2k+ a corner other options will start seeming to make more sense.
The thing that contradicts all the speed issues people discuss with ori's are the amount of guys in my area that run them on SxS's in the 8"-10" range (not even sure if they have res at that size) and they tend to run the trails faster than trail rigs. And I'm not in dune land, the SxS in my terrain are cycling their suspension everywhere.