The Oxydol liquid smells nice, but it's thinner and not as effective. Now, the Oxydol powder I've found at Dollar General is awesome! The scent is pleasant, not cloying, and cleans beautifully. I still miss the green speckles, though.
When I was a kid, Oxydol was a "rotation" brand (bought only if it was cheaper or on sale) for wash day. However, Mrs. Skipworth, one of the neighbors on our block, used it religiously in her GE Filter-Flo.
I've used the powdered Rinso from the 99 cent store on a regular basis when I was out of work and on a very tight budget. I'll have to say I wasn't disappointed with it either. It was the classic 1 cup formula, phosphate free of course. But I'm sure if you throw in a little STPP it should be just fine.