Well... what have you noticed to be unstable? I haven't used Kaos yet, but there doesn't really seem to be any huge issues (other than camera and LED) from what I am reading. I only used EvilEris for about 5 minutes (couldn't figure out how to get a2sd working), so I can't comment on that one. I use White Widow with no problems, working Apps2SD, overclocking, built-in Spare Parts and ADW Launcher... love it so far. I want to switch to KaosFroyo eventually once all the kinks are worked out, but it's gonna be tough to give this one up...