"but bought it anyway as I often use other products from Method and they're pretty good "
I've never tried the Method laundry detergent. I'm curious--but I haven't seen the right deal yet, plus I'm tending to use only powder detergents these days.
However, I have had really good luck with other Method products. A few years ago, I tried several "green" dishwasher detergents, and Method was the most impressive of the group. Of course, it didn't come to the level of Cascade...but now that Cascade is going phosphate free, it probably wouldn't be much better than Method.
I've used other "green" laundry detergents. I don't suppose they have as much power as what is possible, but they work OK for me. When I try conventional detergent, I never see much improvement, except brighter whites. (Which, I think, aren't because the detergent is cleaning better, but because it has optical brighteners.) Although, I seldom have really filthy clothes, and my attitude towards conventional detergents might improve if I had cheap access to European detergents.