After I broke a spoke on my rear Ksyrium Elite I got a pair of used 2004 Eurus. First impressions was of incredible comfort and smothness. The wheels also seem faster. I really like the design. I had to return them because they had been knocked pretty hard and one rim had a ding (this wasn't advertised). When it came time to get a replacement I thought long and hard and decided to go with Ksyrium SLs as a good deal presented itself. The main reason for not getting another pair of Eurus was the fact that truing the wheels required removing tire, tube, and rim strip, and a special tool. That was a killer.
I do like my SLs, they are almost as comfy, a bit lighter, and easy to adjust (special tool needed as well). If the 2006 Eurus had been out earlier I would probably have gone the Campy way. I think they are excellent wheels and all the drawbacks of the previous model have been taken care of.