An often untold story these days is you still need specialistic domain knowledge and a lot of your own data to make good use of fast.ai’s very clever lessons. Being able to achieve state of the art results with copy-pasting & modding any of the Dogs vs Cats image classifiers out there, eg. from Keras/Tensorflow, fast.ai/PyTorch, PyImageSearch/OpenCV etc, is worth almost nothing without your own business or research case, your own data and your own targets / metrics.