Complex computer vision classification tasks based on DenseNet/ResNet approaches; those often could be reduced in depth by some Wide ResNet technique. Keras is super easy there and you get a world-class performance after 1 hour of coding and a week of training, when you know what are you doing.
I mentioned in another comment [0], but also useful here: most of TensorFlow's tools for distributed model training or multi-gpu training will work out of the box directly on Keras, and distributed training is not at all a reason to directly use TensorFlow over Keras. At worst, you have to add in a tiny bit on TensorFlow code on top of the majority being in Keras, but you would still never need to write a significant amount directly in TensorFlow.
I also work on production systems built around deep ResNet architecture for computer vision tasks, and my team does this using solely Keras, including when we do distributed training.
Just adding this thought in case anyone mistakenly thinks you have to start out all-in using only TensorFlow because you might expect to need distributed training at some point.
