https://demuc.de/papers/schoenberger2017comparative.pdf

"Our evaluation confirms that, as expected, learned descriptors often surpass SIFT on all evaluation metrics. However, we also observe that advanced versions of hand-crafted descriptors perform on par or better than the state-of-the-art learned feature descriptors, especially in the more complex SFM scenarios. As such, our paper demonstrates that there is still significant room for improvement for learning more powerful feature descriptors."