For many rooted HTC EVO 4G users, the main reason not to switch to the MIUI custom ROM has been the lack of 4G support. Developers of the main branches have put up signs saying "No WiMAX/4G support, no ETA, thanks for playing" for the longest time, and users have been left to wonder if they were ever going to get it.
Team Nocturnal has an answer by the name of CIUI, a MIUI clone based on CyanogenMod 7 source code that includes the long-anticipated addition. The team has been known for producing some fairly stable and awesome ROMs, so although CIUI is still in its early stages, it's definitely one to watch.
Technically speaking, CIUI is really just CM7 painted/featured to look and act like MIUI, but chances are if you've been on the fence due to 4G, then that's not going to be much of a a sticking point because you'll get AOSP performance and battery life combined with the MIUI launcher, icons, and themes.