The B2320 has a bit higher FEL lift and load ability. If you need that you know what to do.
I had a BX for 4 years and loved it. Just bought a B2620 (pretty much the same as the 2320). A few other things besides the above quote that I like on the B26XX are 1/ 3 speed HST 2/ Easier cold start 3/ cruise control 4/ more substantial 3 point hitch that can take bigger implements. 5/ 4 inches more ground clearance. Might be more but can't think of them now. The only downside I have noticed is the BX was really compact and nice to maneuver around stuff and pick it's way through the forest.