My personal experience with CRKT's AO was a Kommer design framelock that I gave as a present to my brother (this was a few years ago when I was just starting to get in to knives). The difference between that knife and my cheapest Kershaw AO, a Needs Work, is basically you're getting twice the knife for the same money. BTW, these are both about $80 MSRP.
Don't have any experience with Gerber's since the mid-70s.
My understanding is that Gerber and CRKT don't manufacture most of the knives they sell. The majority of their knives are manufactured under contract overseas, however a few models are made in the US by contract manufacturing companies. They aren't bad knives, just not as good as knives made by Buck, Benchmade, Kershaw, and Spyderco. Those 4 companies actually manufacture most of their knives in the US in their own factories. All 4 of them also sell knives that they have manufactured overseas.
Benchmade does have their version of AO, they call it "spring assist". I'm not sure about Buck, but I don't think they have any AO type folders. And after reading a recent thread in the Spyderco sub-forum, they'll never have AO on their knives. Kershaw has plenty of AO knives in just about any price range, while Benchmade's AOs will be higher-priced.
Probably the best thing is to actually go to a store and handle some of the knives you're interested in and see what one you like the look and feel of the most.