Go to the library and ask for Consumer Reports. Even if you don't get the particular models they rate, the article will give you ideas of what to look for -- and what to look out for.
I'd say, though, to ask the length of the normal wash cycle. Some of the new machines are water-saving, but take 90 minutes to wash the clothes. You might not care about that, but you might, and it's not mentioned in the ads.