I use both MorphOS and AROS, but there is a huge difference between them when it comes to stability. AROS is nowhere near compared to the stability level of MorphOS.
Zune is still lacking a lot of functionality to be on par level (well even to MUI3-level)
And Wanderer (frankly) really sucks compared to Ambient.
This is my POW as a user of both systems.
But I do like AROS and I do follow its steps when there is bigger changes.
I also try to support it with my own programs since the API is of a kind I really like =)