I heard of Hugo from Albert perhaps two year ago. But I have never tried my hands on it until recently. Here are some of my thoughts.
I guess the defining feature of Hugo is fast, blazingly fast. It takes ~2 seconds to build the current website with Jekyll, but only ~20 milliseconds with Hugo. The latter is ~100 times faster!
One may argue that the speed improvement from 2 seconds to 20 milliseconds is too trivial. However, it is a totally different experience when the website builds instantly compared to with even a small delay. Imagine how nice it is that you are able to monitor changes in real-time when editing a post or adjusting layout/style. Besides, I have almost nothing on my website yet (only a few posts in pure texts) and it already takes 2 seconds for Jekyll. I can perfect foresee that, as the content grows, Jekyll will unaviodably become unbearably slow at some point.
Besides how fast the website builds, one cares about how well the website looks. As normally we do not build the website from scratch, picking a nice theme is important. Hugo is growing fast and there have been various themes out there already. For example, I tried the theme tale as an experiment and set up a mirrored website here (perhaps with some delay to the main site). However, I decided to stay with Jekyll for now. I really like the current theme but it has not been ported to Hugo yet. Once there is a reliable version out, I will make the switch immediately.
As I do not really have time to dig into the daunting documentation of either Jekyll or Hugo, I really appreciate the one which is easier to use. By far I feel the two are more or less equally easy to set up. However, it should be noted that for ones who are familiar with Jekyll, they might still need some time to adapt to Hugo. I benefit it a lot by watching a youtube tutorial series here.