Caffe2 vs Tensorflow
Caffe2 is intended to be a framework for production edge deployment whereas TensorFlow is more suited towards server production and research. Essentially your target uses are very different. TensorFlow is intended for researchers and servers while caffe2 is aimed towards mobile phones and other relatively computationally constrained platforms. These development goals are reflected in the designs of each framework. For example, caffe2 is used by Facebook for fast style transfer on their mobile app, and TensorFlow is used by Google for, well, almost everything.