I love 'em...there's not much to criticize. Other than the original acquisition costs, I suppose.
The trick is that you have to keep the inner beadlock pressurized to at least a few pounds more than the outer at all times. So for my street pressure (about 18 psi) I need to make sure that the inners are at no less than 21 psi...otherwise the pressure from the outer tire will collapse them (this might be the issue where someone decribed "spinning" a tube). The only thing holding the beadlock and tube is the pressure differential between the inner bag and the outer "aired down" tire. Honestly it's not really much to worry about once you get it setup initially. As long as you don't have a leaking tube or valvestem it's not the kind of thing you really ever need to worry about. Just check the pressures once in a while when airing up at the trailhead.
I've been able to run down to 0 psi without issue....usually around 3 - 5 psi works well on the trail to help squish-out a 38" TSL on a relatively light (5000Lb) rig. You get a "run-flat" benefit with a TireLoc / Staun setup also....if you really tear a sidewall badly, you can still limp it back to camp because the bead will stay put, and you'll have an inner bladder with a reasonable amount of air to ride on.
Airing down is quicker too, since you only remove air from the "outer" part of the tire, not the whole thing. Airing back up is obviously also quicker than a conventional beadlock too.
Overall, there are some nice benefits to having them....don't forget, they are super light too, so it doesn't add a bunch of extra wheel mass...less inertia is always a good thing when it comes to reducing driveline stresses.