I used over 300 gal of ClearOut last season. About the same the year before on my ag applications. Last I checked, Clear Out is formulated in China. Quality control is much less there than American based glyphosates. As a matter of fact, we had severe damage on "roundup ready" cotton last year from clear-out applied over-the-top. Agronomist confirmed that clear-out had caused damage statewide to glyphosate resistant crops. The damage was due to poor surfactant quality formulated in clearout. If you are seeking non-selective control,which I assume you are, it is a satisfactory product. We still use a little for that purpose, but not on GMO crops. Clear-out led the price break on generics, but most of the others have matched their price. I have seen bulk prices as low as $12/gal. Glyfos xtra has been a good generic for us and more consistent.
The difference in generic glyphosates is the "loading" of surfactants. All ai's are equivalent and most come "out of the same spigot" regardless of brand. Without a doubt, Monsanto's Roundup with weathermax technology remains the premium glyphosate on the market, but you will pay dearly. It has a higher ai and patented surfactant technology.
As stated above, drought and cool weather will decrease performance. We allow as much as 4 weeks for ryegrass kill during cool months. Also, you might consider at least a 3% solution for spot sprays. Probably more info than what you wanted, but hope it helps.
