That's debatable. I ported Galnet Miui for the D2G and it's a piece of shit, other than being a version of 2.3.7 with 4.0.3 elements and a pretty veneer. OK, that's not fair to say... it's a decent ROM, but it's still GB with ICS elements, being touted as pure ICS and has too many restrictions. It runs good and looks pretty, because they cherry-picked the ICS elements like battery use/standby and theme, but left the core GB OS so it would work on older devices.
The problem is they rely too much on proprietary apps like their messaging app. While I liked the Miui Messaging app, you can't remove or freeze it, because ANY sms/mms app uses it to send/receive messages. Same with the browser, as I recall. From a dev standpoint, proprietary apps are no better than bloatware, so I've never been fully onboard with Miui.
The Galnet release looked pretty and *seemed* to perform like ICS, but it had limitations and still looked like a damn iPhone that required an alt home app like ADW to hide un-used apps... you know, like messaging and browser, since you have to keep them, even if you don't use them?
That said, I'd gladly try Miui (preferably Galnet) on the Spectrum. They'd have to port it from the Optimus 2X, which might be an issue with the different radio, but it's a start:
Old Gingerbread Roms | MIUI Scotland