I've heard nothing but good things about the Black John. Let us know how it goes for you. I haven't played with any of the 2M range but I do have a Concorde Pro/OM40 frankenstein (Pro S body, OM40 stylus) ala KAB that is pretty good on the SL-1210. I've been told the Black (not the Red or Blue) betters the KAB recipe in every respect.
That is a great combination on the SL-1200. Have used that one myself with excellent results before upgrading the arm. Super easy to set up too.
If you go back to a headshell on that arm, check out an NOS Ortofon VMS20. You can usually find em for about 125, and they are scary good.