I've been flashing each of the nightlies as they came out and I'm actually on 527 now which is post RC3 but I've not noticed any substantial changes. I usually flash them for any stability improvements that come along. I can tell you though that you can flash with confidence. I have no problem being a guinea pig so I go ahead and try everything as it comes out and let all of my report data go back to CM so they can make improvements. Recently, I have noticed that for some reason, scramble with friends force closes upon booting up the phone but I don't know whether that is related to the ROM and it's not really that big of a deal.
all in all i would recommend the update.