Have Had An 18" "Kenmore"
Rebadged Frigidaire dishwasher for almost ten years now, and while yes it does not hold as much as it's larger cousins, the job gets done.
True one cannot fit large items in there, but that was expected wasn't it? I mean you aren't going to fit the same amount of laundry into a portable small washer as it's full sized cousin, are you?
Run ours either daily or every other day, sometimes longer depending upon how long it takes to get filled. Give the thing plenty of *hot* water and decent dishwasher detergent, results are more than fine.
What doesn't fit into the dishwasher, gets done the old fashioned way. Still am that glad to have the unit versus having to wash everything via hand.
This is my story, and am sticking to it!
L.