Yes depends on the size of your room, Jason added an 800 to his 600 and decided he didn't need both, he loves the 800 yet intends to sell the 600 because it doesn't incrementally improve the sound that much in his room.
Of course I'd love to have two because my wife feels the 800 is too boomy, however, after I tame the room response perhaps that will change; right now I'm running it a tad hot for fun, before when she said it sounded like "an earthquake" I swear it was during blu ray playback when most likely it was supposed to sound that way.
