Not really an appropriate use of force - if your hitting someone in the head/neck/spine area with a baton, you better have a damn good reason to be using deadly force.
Batons are for striking limbs, arms, legs and doing damage to the joints.
Its hard for someone to attack when their elbow or knee is busted.
They also work for disarming, break the wrist holding the knife, again they will find it hard to continue the attack.
Batons arent just for beating on people with.
For what its worth, i found 24" to be a good length - 21" was to short for me (im6'6") and the 26 was a bit big and heavy for my liking.
I had Monadnocks, a 24" friction lock and a 22" autolock
The 22" autolock was cool, easy to collapse, but it didnt feel as nice and solid as the friction lock baton, it was also bigger and heavier when closed.