My plan: trade my xxb with a 100-400 as I need the extra reach and later add a 85/1.8 or 135/2 for portrait/events. 小竹炮 (or XB IS) is a very nice and versitile lens but for the type of photos I shoot now, I don't feel the urgency to get it.
Anyway, this is just a plan and don't know when I can actually excute it.