"if the dishwasher shoppers don't hear the
machine running in the store connected to water they won't really be
able to compare it. "

Then it must be pretty hard to compare them, because I've never seen
them hooked up for comparison. It's very rare to even see one hooked
up at all, no? I can recall seeing one demo, maybe at Sears, long
time ago. But that was one machine and no way to really compare it to
any other.