Of the three shops I went to two of them were saying one copy of each book per customer which I felt was generous. One (the store I usually go to) did keep some of the free comics (the non-gold ones) behind their counter though and you had to ask for them. He said he did this because in previous years people came in grabbing every book they could but they really had no interest in all of them, they were just grabbing what they could. Limiting it to people who knew about them and asked for them seemed to limit that. I saw that first hand when I went to the other store, they had all their books out for grabbing and when I asked the owner about some of the non-gold books (Atomic Robo for instance) he said that they disappeared early. He bought a lot of them but not as much as the cheaper gold books and with everyone just grabbing everything they could they disappeared quickly.
The crowds were also very different. The local store was quiet as expected. Their advertising for the event consisted of two 8x10 pieces of pink paper in their windows with "Free Comic Book Day" in small print. The second (my usual shop) was also fairly quiet when I went in but the manager said he was getting steady business. It had a couple families in there shopping and it was cute to see the kids expressing interest in some comics. The third store was a mad house. They had a lot of people in costumes having their photos taken and there were a lot of families with a lot of kids in the free comic book area of the store (the front part). There were also a fair amount of people browsing the comics (further back in the store).
In the end, I ended up buying Atomic Robo volume 1 and We3. And of the free comics I got the Mouse Guard, Stuff of Legend, and Atomic Robo (which I ended up finding in the closest/quiet store).