I'm using Artist / Album.
I like to use group view. However, as a result of poor internationalization, there is no choice. Any of non alphabet name are just ignored in group view. Those are not appeared even in <others> group. BTW, is it possible to use first character in non alphabet name as a key to group them?
Moreover, Artist and album list is not sorted properly in Japanese character order. MC is sorting it by using code number, but Japanese are not sorted in UNICODE. As a result, random Japanese order. In general, real internationalized organizing software has their own sort routine. Wish if MC9 thought about internationalization issues much more. Current implementation is still worse than MJ7 (it doesn't assume anything about internationalization, so it worked fine on localized OS like Windows Japanese Edition).
On the other hand, hard disk location view is interesting. I didn't know it. However, in pane view, it shows only 2 or 3 drives in a pane... So, it seems not useful for now, though.