Cold washing in a puddle..
The Neptune does use less than a top loader, but more than any other modern front loader. It has yet to fail me as far as cleaning goes, even though I havent had it long. It is a HUGE improvement over the Daewoo twin tub I was using.
The Daewoo is a modern reversing impeller machine, and I have come to realize that the impeller machines (with the exception of the old Hoovers), are a joke. They dont agitate heavily enough to actually clean things on their own. Socks always required pre-soaking and hand scrubbing before washing to get the bottoms clean in the Daewoo. Not so in the Neptune. Chuck them in, load the detergent, bleach, and softener dispenser, hot/cold setting, stain cycle, heavy wash whites, they come out perfect and just like new.
If they would ever so slightly increase other front loaders water usage, more in line with what the Neptune uses, there would be no more of this washing in a puddle business. Clothes would come nice and clean, and people would still save water over using a top loader. (No I'm not anti top loader. I love the vintage ones, and generally they do awesome jobs of washing. But all front loaders are not evil either. A lot of guys on here have vintage Westy front loaders and always seem happy with their performance as well.)
Temp wise, I use warm for nearly everything, (hot for whites, cold for delicates), and I like that the water is always actually warm. In winter here without the tempering valve set up, the warm setting isnt actually warm, just slightly less cold, lol.