If you want accurate colour then the 2400 is easier to profile, has less metamerism and produces more neutral B&W.
If you want to keep both printers, you might be better off dedicating your 2200 to B&W by using third party inks with it, and using the 2400 for colour.
Having owned both printers I much prefer the 2400 for both types of work.
If you want to explore doing dedicated B&W on the 2200 then this forum has lots of useful info & helpful people
http://groups.yahoo.com/group/Digita...WhiteThePrint/
HTH
Alan