I had the occasion to try both of these places in the past few days.
Overall, Harvest is considerably more crowded but is a more pleasant place to eat- with somewhat better food than East.
Harvest: limited but tasty sushi (red clam, octopus, crab rolls, etc.), dim sum fairly standard but not bad quality, some korean foods including kimchee, good duck, excellent chilean sea bass, well prepared pork dishes of all sorts, good seafood stews, good cold tripe. Pleasant staff.
East: sushi fair (california rolls, tuna rolls, cucumber rolls, no nigiri sushi),
dim sum doughy, overly sweet selection, nothing outstanding even though East operates a dim sum restaurant across the hall. Interesting pork congee but overly salty. Fish only fair. Most meats pedestrian quality. Duck feet poor.
I was the only non-asian in the restaurant and was seated away from the main dining area at a corner table, the only one without a tablecloth. Some of the staff was rather surly. I don't think I'll go back again.