We have bought a few over the years because of moving into new houses!
Last two times, I subscribed to Consumer Reports online for a month ($5.00) and researched, researched, researched!!!!
Both times, we ended up Sears Kenmore... Usually a CR Best Buy recommendation.
Although there are lots of others that got great ratings, we've always been pleased with the cost, low maintenance, and Energy Star rating (low water, low electricity) of Kenmore. ALSO, we do not have to 'wash' or 'rinse' the dishes before putting them in and they come out sparkling clean. EXCELLENT food grinding motor.