heres a noob perspective. i have started down this road, read just about everything i could find here and elsewhere. this is my 1st ak build and have read the warnings that this is an advanced project for a first timer. that being said, what i have learned from the many post is the gas-op is a tweakers special. it will require adjustments to get right. blowback on the other hand is straight forward,relatively speaking based on experience. as soon as my mags arrive i will start working the pieces. i am a true glutton for punishment and tend to start with the more complicated option. my thought is if i can pull this off then everything else is cake. the azhonky builds and writeups are the best i have seen. the 2xtm posts were good, but for some reason i cant find it anymore. read everything, when you think you have a good grasp of the build, read some more and ask lots of questions. my vote is blowback on the first on and gas-op next.