Jennifer: My understanding from reading their materials and the MSDS is that it is majority DEG with sand added.
Marc: Two chemical engineers debating a topic very quickly gets tedious for the participants and immediately boring for everyone else, so I'm not going to start.
Colin: I think you are right to be concerned about the toxicity of DEG (or any other component of material you use). However, the toxicity of DEG is similar to that of methanol and ethylene glycol - two other ways to blind or kill a mammal (and the only first aid situations I recommend oral ethanol for), and many of us burn methanol in concentrations from 5 to 50+% in alky stoves.
My take: This stuff is spendy. $8.50 for 6 ounces (which includes some sand) is, ballpark, $200/gallon of gasoline equivalent. So be glad your car doesn't take this as fuel. Gelled fuels are also low output compared to liquid-fueled or canister stoves. It IS handy for fire starting in a pinch. It IS handy if you want to warm a can of beans when the power is out. It is NOT a new concept - I was selling "Fire Ribbon" 30 years ago in a BPing store, but not to ULers. It's marketed to start a wood/charcoal fire, but we'd suggest it for priming your Svea 123 or Optimus 8R more neatly than spilling liquid white gas all over. It's still available, as is Coghlan's "Fire Paste" (probably just a relabeling) through Amazon, True Value, etc.
What's new with this stuff is that the vapor pressure must be low enough that they can ship common carrier and on airlines. That's a big plus in a few cases, say if you go backpacking on a 737 into a place with no stores. I might be the only one on this site that does that very often (e.g. Adak in the Aleutians last October). But on the jet to Kauai last month - I'd skip it and just be prepared to use 1-pound propane bottles or suck it up and use Sterno - which just as low performance as these gels, but available cheaper and locally (all of this because I couldn't find butane canisters anywhere on island). But when I'm flying in on a DeHallivand Otter or a Cessna 207, the pilot doesn't care if I have propane, butane, white gas, pepper spray, guns, and knives. They'd kind of wonder if I didn't.
Back to the toxicity - No, don't eat it. Try not to breath the flumes. That's true of everything we burn (wood, tobacco, gasoline, charcoal, etc). It's more true for these low-temperature, low-efficiency flames. This isn't a pre-mixed burner like a butane, propane, white-gas BPing stove or the natural-gas stove you have at home. Therefore there are more unburned fuels in the exhaust gases. Would I use it? Yes. I'd try to stay upwind. I'd only use it in a pinch. But it is helpful to be reminded that some options are still around decades later.
Do their weasel words "designed to be non-toxic" rub me the wrong way? Yeah. I studied and graduated in ChemEng, but I've spent decades cleaning up after my former classmates. "Less toxic than Botox, more toxic than dirt" - I'd rather they bracket it than gloss over it.