Just as a follow up I started working with a tonfa after I posted this. One thing that I do like, in addition to the nice jab to the belly, is that the energy transfer is different than with an expandable baton. With an expandable baton any energy to put into your strike also transfers right back into your arm. When you swing a tonfa you don't get the same energy transfer to your arm because the baton can swing back. At first I was thinking this may make for a weaker attack but I hooked up a few sensors to my BOB and indeed I was actually delivering more force with the tonfa than a Kali Stick or expandable baton. I can see where it would be much much harder to learn to use effectively though.