KR sucks and got overrun with unironic syndieboos/Internet communists long ago, it's been years since they axed fun longstanding content for being 'problematic' like Ungern-Sternberg's rampage as Genghis Khan II or Organic (Integralist) Brazil being able to go to Africa. Conversely AFAIK the CSA is still a leftist wish fulfillment fantasy, including an event about a sexual revolution being brought to wartorn 1930s-40s America by no less than Magnus Hirschfeld and Harry Hay (literally a staunch NAMBLA supporter).
Kaiserredux is where it's at. They also have a vastly more sensible setup for the 2ACW in general (incorporated from another mod, Home of the Brave) including things like the Western Feds being a separate tag so MacArthur can focus on fighting in the East without getting divisions easily encircled in the Rockies, Huey Long leading his own agrarian-populist faction in the Great Plains while an alliance of the KKK, Dixiecrat political machines & big business occupies the South (he hated those guys and was hated by them in turn IRL), New York City and the Southern blacks being able to rise up as independent factions in their own right instead of being folded into the CSA, and the CSA's leaders & subfactions reflecting actual left-wing thought from the 1930s rather than the wish fulfillment fantasies of sexually frustrated commie troons on today's Internet. Other than that (by far my favorite aspect of KX) they also have so much more content than base KR it's not even funny, including the lost content for countries like Mongolia & Brazil which they've even expanded on.