I used to be a HUGE CM supporter.
Still am, and am actually ON CM currently...but I flash between that an MIUI constantly.
I'll quickly vouch for MIUI here.
I had avoided it for my entire android experience. Didn't want to touch that crappy iPhone Kangerang!
I flashed it out of curiosity a few months ago...
And have been happily sitting on it as my daily driver (a lot of the time).
It's themes are gorgeous...and even simpler to flash that CM7's TMobile theme engine themes.
The lockscreens? Endless. And again, gorgeous. Super cool customization here.
ICS rip-offs. Blur rip-offs. iPhone rip-offs (blegh!).
The dialer is very blur-like...something that blur does right.
You type (T9-like) a person's name and they pop up in the menu for a quick call.
Menu+Down Volume = Screenshot
Menu+Volume Up = Temporary Full Brightness (Ever been in a sunny area and NEEDED this to see?).
The typical "pull-up" menus from android turn into drop-down menus.
The call-answer function is, again, beautiful. And allows you to quickly ignore and send an auto-text stating that you're busy.
Endless Boot-animations...again, in the theme section.
System sounds were recently added to MIUI themes...
With a touch of a button, you can change your lockscreen sound...keyboard sounds...selection sounds...instantly.
MIUI, is classy. And a very nice ROM.
Try it. If you were like me, you'll be happy you took the plunge.
*As a note, I do NOT like the MIUI launcher...
A custom one quickly fixes that.
As far as AOSP...
What do you like about it?
I mean, I don't dislike it.
But you can flash the gallery onto MIUI.
And the AOSP messenger is nothing special (I mean, it doesn't have features that others don't).
Again, the "blur" feature here is VERY nice.
These look pretty AOSP on MIUI...
And, again, the "ICS MIUI" builds that are currently out are not only not truly ICS...but aren't even official.
MIUI's Facebook page actually posted a bunch of screens this morning of what they're working on for the official release (with UI enhancements, as one user here suggested he wanted).
New Dialer was shown...along with the new app manager (ICS of their own) feature.
Don't just believe the hype like I did...
MIUI is actually pretty goddamn sweet.