I think the Black stuff is really good.
I like the preamp, it has some size to it, and is smooth. Great on certain things...
The HMX function is worth it though anyway. As a line in device the black pre is good. I found it more entertaining than Duality/SSL VHD. However its more of a one trick pony, but very fattening. Great on synths. I think it would suit hip-hop guys looking to add some girth.
EQ is cool and quite tunable to be musical and somewhat surgical.
GLO is interesting but less 'apparent' to HMX from what I remember. It's a unique feature though, that should be listened to.
Comp was OK, great at aggressive squishy stuff, less amazing at subtle stuff, but I really liked it and didn't spend ages listening to it.
The MICO as I understand it, is the same preamp as the ASP008 or 8024 console, which is a non-transformer, non-completely discrete (the Black is TX/Transistor) hybrid design which uses low noise transistor input stage and integrated circuits - so cleaner and leaner than the Black preamp.
If you like that vibe - then the MICO should be a nice tool. HMX circuit is there to add COLOUR to the cleaner/leaner preamp - and believe me it WILL thicken it up and make more difference than going through the BLACK preamp transformers. It's pretty un-subtle. So you'll have a few distinct flavours in the one box.
The Vari-phase is useful too, plus it has pads, which a lot of other Audient products do not feature - a must for me personally.
Overall, MICO looks good and well thought out, plus I think they will expand the half rack range to add some other cool tools in a small package. I haven't used one yet...
-T