I don't know if it's been posted on SMF, but my notes say avocado can have anywhere from 4% to 9% unsaponifiable content. That's high compared with the other commonly used soaping oils.
Avocado is otherwise similar to olive oil, but with a higher linolenic acid content -- that might be where the DOS is coming from. I used avocado at 10% to 15% in one recipe for a soap that I wanted to be extra gentle for my mom. Made a few batches of that and have had no DOS after about 1 year of testing.
I don't see a huge difference in the soaps with avocado vs. ones without avocado, but that's on my skin and with my water. It certainly has label appeal and does make a mild soap. It's hard for me to find avocado here in the boonies of Iowa, so I've gotten away from using it in soap, but I have no complaints otherwise. I seem to recall Carolyn (cmzaha) uses avocado quite a bit in her soaps.