I went today (9/14/07) and auditioned most of them (not the 684 2-1/2 way). With all respect, I wouldn't consider the 600 series entry-level but I guess that's a matter of opinion. Perhaps their 300 series is. Anyway, the 686 replaces the 600, the 685 replaces it seems both the 601 and 602, the 684 replaces the 603 and the 683 the 604. Remember the Series 3 had 5 units and the new series 4. The new one doesn't offer a large bookshelf such as the 602 was.
We first listened to the 685 vs a pair of the DM601 S3's. We listed to Larry Carlton's Collection CD. Overall we both (sales person and I) found the 685's to be more open and yet at the same time tighter and warmer than the 601's. They seem to fill the room with more ease than the 601's. On Small Town Girl when listening to the 685's, the bass guitar licks (not the bass response) were very prominent. I'm taking about the actual finger picks of the strings. When we switched to the 601's, the licks disappeared into the background and no longer stood out. The 685's seem to produce a superior soundstage meaing the music seemed to project all around us in 3 dimensionionally more than the 601's. I'm not trashing the 601's or the Series 3 by any means. I have a pair of the DM601's and DM603's and am not about the trade up. I luv'm !! But side by side, these were my impressions.
We then switched on the 683's and of course the sound was fuller and deeper as you would expect from a floor stander. Same characteristics as the 685's but again fuller and deeper. The little 686's by themselves with no sub were simply amazing. To hear that much bass and imaging eminate from these little guys in the large demo room we were in greatly impressed me.
The new 600's are assembled at a large Rotel plant in China. That is why B&W can offer them at the same price levels as the Series 3. The technology used is taken from the more expensive 800 series and incorporated into the 600's. By finding ways to produce some of the 800 series components cheaper (i.e. kevlar cones), they were able to bring these to the new 600's. Go to www.bowers-wilkins.com to study up on the technology and the story behind this new line. Thanks for listening.