The Alpha build of CM 6.1.2 that was released earlier this month--you know, the one that finally brought 4G to Cyanogen on the HTC Evo--has been updated to version 3. The ROM's latest build (by Shinzul and toastcfh) greatly reduces the amount of time it takes to start WiMax when 4G is turned on.
In the previous versions of CM6+4G alpha, it would often take a couple minutes or more to fire up the Wimax radio. With this new update, the Evo connects to 4G within 10-20 seconds (roughly the same as on a Sense-based Evo ROM).
While labeled as an Alpha build, the ROM is widely accepted as being completely stable in its current state. One of the most noticeable "bugs" is a purely cosmetic one: the lack of a proper 4G icon when connected to a Wimax network.
Of course this ROM is based off of CM6.1.2 source (Froyo). The CM7 Gingerbread nightlies have yet to incorporate 4G.