I did an "experiment" (err...really it was out of laziness) by putting in some pots and dishes that had been sitting in our sink for a while with a variety of yummy food residues. I didn't pre-rinse any of them. And you know what, most of the came out pretty clean! There were a few rejects that I had to put back in after I took out the clean dishes...but those were the ones with more difficult residues (and of course, it could also be a function of the dishwasher too).
Overall, I really like the TJ's powder. It didn't leave any soap residue on any of my dishes and my glassware is all sparkly and clean. Also, the pour spout and cardboard box are solid construction. And the powder isn't so fine that it sprays all over the place when I pour it into the soap container thing on the inside of the dishwasher door (yeah, I get pretty technical with my names for things). And of course, the biodegradable surfactant, phosphate-, fragrance-, chlorine-, dye-free thing is pretty sweet too.
