Avocado is fine according to this guy:
http://grillinfools.com/blog/2009/04/01/smoke-wood-what-kind-is-best-well-it-depends/
Haven't used it but where I get my smoking wood at the Woodshed in Orange, California they sell it.
I've use it twice. The problem I found was it likes to burn at hot temp. For smoking it gave off a bidder smell. For roasting a few birds it did find.