I was up there with the people that supported MIUI and loved it. However the airplane mode just got to be too much for me and then I ran in to other bugs where I could not get data at all to work, still had service, but data would be out for 58 of 60 min in an hour. This was at the time the CM7 for GB got done. I have to say I think this version on CM7 is running great.
Speed = Advantage to CM7GB
Theme options = MIUI, like being able to mix and match
Battery Life = CM7GB, I think this is because of the kernel because MIUI beat the original CM7
Launcher = I really locked the stock launcher on MIUI, but I am back on GoLauncher and have no issues.
Issues = CM7GB, I have not had any issues that effect my day to day use. MIUI did not really have any issues until the end and then even when I tried to go back to the original release.
Revnumbers has done a great job on this release.