I know DUS is not that bad, I stay there regularly... But mostly at properties a bit below the level that is discussed here. For instance the Hyatt in Dusseldorf works for me, but is no comparison to the Andaz in Amsterdam. Also not in price...

Personally a good hotel in a city is more than enough for me. I save the luxury for when I'm on holiday and get to enjoy the benefits a bit longer. But I sometimes stay for work when others are staying as well.... And it's pretty easy to find somewhere that's good.