In the past, I've carried: PR24 (6 yrs, found it bulky, yet very effective and useful for many situations); Mondanock 26" straight expandable baton (stout, button lock for ease of closing).
Currently I carry an airweight 21" ASP. I like it very much. Very light, very compact on my belt. I can't understate the importance of those two qualities. If I have to strike someone w/ it, it'll hit probably 50% as hard as a PR24 and maybe 75% as hard as the Monadnock, but it'll still be enought to get the job done.
So what if I have to slam it to close it? Not concerned about that. Also not concerned about silent deployment - the noise it makes gets attention, which, enough of the to matter, makes the person stop what they are doing.
For training, I still use the Monadnock, as it's mure more durable.
SF