I have not tried IoD but i have heard GREAT things about it.
I like tropiclean..especially the NEEM shampoo..i love how it lathers and it seems to get dogs really clean.
I believe tropiclean also made the "spa" products sent to petco for their monthly scents and such..and i always liked those shampoos. Hardly anyone ever sold packages so I'd use them all the time on my own dogs or on clients I really liked. They would smell really good and seemed to get dogs really clean.