I use this for not it's intended purpose, but as a random midi-gate. With proper settings, you can get only 20% notes through, or whatever you might need. It's not really meant for that so there's few caveats, as in you need to define the note length which also happens to define the frequency of the "gate". So it's not going to rally match your incoming notes perfectly.
But it's extremely lightweight, does something that I haven't found anything else to do. Except Hypercyclic which is unstable & available only as 32-bit -- also is way more random. Actually to be honest, I am not sure it even can do the same thing... but I am erring on the side of caution. I seem to recall it tends to prefer adding random notes instead of working like a gate.
But RandArp also works as a random arp, as intended. But I never use it as such.