It will probably be a perfectly good machine for you.
I am becoming increasingly suspicious of internet ratings for anything - as mentioned previously, dissatisfied customers will go all-out to rant, since the internet is a great forum for airing grievances, whether they be real, perceived or just flat-out imagined.
KitchenAid dishwashers are made by Whirlpool now, and given that, you have about a 90% chance of getting a machine that survives the warranty period.