I haven't yet used it for anything, but I did look through the docs and demos. It's a really cool piece of software. They wrote their own deep neural network library. And they gave it a very nice user interface for building and experimenting with complicated neural networks.

It's not only useful for research, it might be a great way to get non experts and beginners into AI. They are also experimenting a lot with reinforcement learning on video games. This is a much more general branch of machine learning. Deepmind impressed a lot of people and made a lot of money when they demonstrated playing some simple atari games. These people are aiming for AIs that can play Space Engineers.