Both are upscale clubs, Nachtresidenz has a longer tradition and is closer to downtown, whereas Rudas is in the Medienhafen, ~10 mins by taxi from downtown. Do note that many Dusseldorf bars uphold a dress code / door policy, including the two mentioned. This can be quite random, as with many such establishments - just be aware of it and be smart about trying to get in during busy hours, especially as a group.

My advice, if you're into beer: Skip the clubs altogether and do a full fletched Altstadt tour instead, visiting all the 5 local breweries and taste all sorts of Altbier. There's some 250 bars to choose from - and after all, that's what the Altstadt is all about Good chance you'll be ready for bed by the end of the night

And if not, a little less posh, but fun: Mauer in the Altstadt.