Shopping for the best dishwasher that $600 can buy....suggestions as to what/where to buy?

I've never ever had a dishwasher. So, I'm new to this. I want something basic, but good quality. Also would need to have it professionally installed. Any good or bad dealings with stores like Best Buy, Home Depot or Sears? Chances are, we will buy from Sears........??? Thanks to all in advance.