Actually, I don't think this HAS been answered a million times over for people with 3a/3b hair. I have the same hair type as you, and got the Coppola keratin last night. I had searched for about a week on this site for specific answers/pictures of the results for people who have 3a/b hair, and couldn't find anything. (I did hear, over and over, that the Coppola treatment apparently doesn't work for people who have 3c or 4 curls--but that's not our hair type, so that information is irrelevant.)
I took a "before" picture, a photo last night immediately after the keratin treatment, and will take another "after" photo once I can wash it (Saturday afternoon or so). I hope this will help people who have questions about the treatment for our specific hair type.
Now that it's the next day, I don't think my hair feels any softer. It didn't burn my eyes or anything like that, and in fact it had a kind of pleasant coconutty smell--so the process itself wasn't too bad. (Also, the stylist who did mine, here in NYC, is extremely fast--I was done in 2 hours, not the standard 3. My hair was washed twice with clarifying shampoo, then blow-dried. The keratin was painted on, then blow-dried again, then flat-ironed--with two irons, working separately. Much quicker than I thought!)
Hope it went well for you!