Dishwashers can be freestanding or built in / integrated and generally come in 2 sizes, slimline or full size. Slimline dishwashers are 45cms wide whilst full size are 60cms wide.
Quality is not just the number of programmes they offer, lets face it, how many of us just shove the pots in, close the door and turn the machine on......a good quality dishwasher should be quiet, and the quieter - the better
Noise is measured in decibels (db), look for a machine with less than 50db - the quietest will be around 40db or a little less