I worked with it _before_ it was released, and with DistBelief before that. For a long time I considered TF to be the best option for the class of problems I work on. I was also extremely skeptical of PyTorch, but it won me over. Now that I'm no longer on a steady diet of Google Kool-Aid, I have the luxury of picking the best tool for the job. For a number of things that tool is made by Google (protocol buffers, gtest, gmock, grpc, some other things). But not for ML.