I'm afraid that your best bet is probably going to be Oracle itself. We don't hear much from people using ADF in this forum. Most people here use Primefaces, Richfaces, Icefaces or Myfaces, although ADF is implemented in one of the MyFaces modules (Trinidad, I think.)
I have little doubt that Oracle would be glad to provide training at excruciatingly extortionate rates and will likely even give you a nice piece of paper for taking the course, but this is technology that is widely used in most shops.
Customer surveys are for companies who didn't pay proper attention to begin with.