Xpantastic!

a bit OT, but still interesting ...

>  I only played one briefly some time ago but am now potentially being
>  offered one for sale or, gasp, in exchange for my xpander!  So I am
>  wondering if anyone's used both and able to comment?  pluses/minuses?

This is probably the best Chroma resource out there.
http://www.rhodeschroma.com/