Suppose it depends on the action youre referring to. But its not hard to spend or save $100 over the course of a full build, so if it helps, go ahead and assume $700 instead of $600. I personally buy blanks on sale and have LRI do the chambering. Many people here arent using retail prices for anything. Buy second hand, on sale, etc. (that includes the AI we're hypothetically comparing to. At least those are the assumptions Im using for comparison).
As to who I would call if something didnt work? Guess it depends on the issue. For example, I had an issue with my Nuke and an early geissele trigger. Geissele handled it (very expeditiously I may add). Bad headspace or poor threads would go back to the 'smith that chambered it. etc.
Again, no one is trying to talk anyone out of any AI. Like I said, its the best rifle Ive ever owned. I hope to own an AT w/ the AX buttstock at some point in the next few years. But for me, and many who not are not professional shooters, LE, Mil, etc. AI is overkill and you will get 90% of the functionality for $1500-$2500 less (depending on features you value, your feelings on new vs used, urgency, and shopping skill). All depends on your needs, priorites, and obviously disposable income.