It's the primary powder that I use in my Neptune 7500. I cut it 1/3 with STPP, which helps to get out ground in dirt and greasy/oily stains.
I'm working on a bunch of the stuff, in pails, that I got from Orchard Supply Hardware (OSH) a few years ago. I gather the formula hasn't changed much, although now i see that they've replaced the version with "color safe bleach" with "Oxyclean". I use the "color safe bleach" variety on whites on the hot setting, also cut with STPP. Gives great results.
Regarding cold water use... it's a good idea to use warm or hot water with any powder. The washing soda, which usually makes up the bulk of a powdered detergent's active ingredients, doesn't dissolve well in cold water. For cold water, a liquid might be best, or maybe Cold Water Tide HE.