Both are considered organic; both will kill topgrowth without doing substantial harm to roots, especially deep taproots or rhizomes. If you want to use organic methods and only have time to do it once, have you considered solarization? Chemistry does not seem to be your answer.

There is a reason products like RoundUp/glyphosate are so popular....they are effective. And exactly how toxic they may be compared to other products is up for some debate.

Burn Out is just horticultural strength vinegar. And it comes with its own set of cautions. It is extremely caustic - you need to wear protectve clothing and goggles when spraying - and can alter soil pH rather dramatically (although temporarily) at least on the soil surface. And it is not translocated into the root system so perennial weeds will grow back.

And I am not familiar with Pulverize so did some research. Its active ingredient is ammoniated salts of fatty acids, which is pretty close to the active ingredient in insecticidal soap. And you might want to read up on maleic hydrazide, which does not sound like a very benign addition to this product. But that is what supposedly gives this product its systemic effect.

Thanks to both of you. I have tried laying down cardboard I get from dumpster diving into the recycling bins of our large appliance store. I put wood chips on top to keep the cardboard in place. But in a few years it breaks down. So this is a great solution for a while. Have not tried solarization; that would be a lot of plastic for 1/2 acre. I think I'm back to Roundup.