Disclaimer: I had very weird experiences with all of those.
Complex without reason and requires a lot of effort(?) just to get the job done (configuration files, metadata, themes, and other shenanigans), and the result is literally HTML5 instead of a saner markup like XHTML. Imho, HTML5 sucks anyway. Hugo has very poor documentation, wonder if it even has a manual page lol.
Perfect for a blog like the one at codemadness, can generate various kinds of feeds, like Atom, RSS and even twtxt. Every page requires its own setting, like metadata and the output filename to use. The resulting site can be rendered on any browser without any issue. A bit complex but it gets the job done really well.
Doesn't have an output format by default, since you have to design the layout yourself, which is well, okay. It generates the pages from Markdown input, and metadata is included in a yaml-like syntax on the document's header, separate from the main text. It is also very extensible with tools you can write on virtually any language, even shell script, and then invoke them as if it were a built-in command. Pretty neat I guess.