I would never try to dissuade anyone from building their own AR,,however i wouldn't make it my first AR,, i think a factory made rifle has a better chance of being better "built" and more reliable, plus any problems u can send it back.
While building one yourself is fun and a learning experience, if u never get it together right, your back to fiddling with it for weekends on end, sending it to a gunsmith, or begging your more experienced friend to diddle with it.
Its also been reported that during training at Blackwater not one "home built" AR made it thru the course, some just rattling apart.
I really can't trust my life to a rifle that "might" work even if i'm the one who put it together.
I have a few AR's , and i have a few lowers i plan on building, so have fun, buy parts, build what u want, but be sure to test your rifle and make sure its made to last.