This should make it easy to do comparitive test/measurements
between the two and maybe experiment with any wishlist extensions
you want for the revised API (which is WIP I believe), using
the underlying AVL implementation.
I'll do the same thing for Data.Map soon, though it'll probably
have to wait until next weekend now.
This module is completely untested but the underlying AVL library
has been pretty thouroughly tested. So it should work OK. If you
use it and find any problems please let me know.