In my mind, GE and Whirlpool are the best buys. Stay away from the "lesser" brands at HD like Americana, Maytag, or Amana. Also stay away from LG.
That said, now what you get in terms of the price range from maybe $250 to $750 is more spray arms, may more powerful spray, some bells and whistles, and the biggy: QUIET.
An entry level dishwasher will perfomr ok and probably last for years. If that is what you can afford right now, go for it. Work with it....rinse the dishes quickly right after meals, before loading into the machine. Don't put dried on egg in there. In general, you will be fine.