I have experience with owning the 400's, purchased 800's and now am going back to a another pair of 400's. I only know the 400's, but remember there 4 ohm speakers, making them effcient relative to amp wattage. I played them through a Plinius SA100 MK111 100 watt per channel amp (rated for 8 ohm's) and the bass extension was amazing! Very nice detail, excellent sound stage, depth, openess. I'd take the Dali's in hearbeat, besides I see a lot of the Adagio's used on the Audiogon. In terms of price, its probably easier to buy a used pair then the Dali's, you should really audition both.