I am basically in last few days seaching for the answers of very same question. I have selected jekyll because of following reasons…These are all personal based on my background, preferences. Even though, I am a developer, I am not a web developer. I know concepts, but have very limited experience in web development. I am very novice at javascript, html, css etc. But I have some experience in ruby and python…
Jekyll seems to have the best documentation and greater selection of free themes which is important for speedy startup… If I were proficient in web development, I would not care much about tutorials and documentation…
I find gatsy very generic not specific or ready to use solution like hugo or jekyll. I far as I can see, you need a good background at javascript and specifically to the react. javascript world is very much convoluted and there seems to be thousands of things going on, there are many wrappers, libraries that generates javascript etc. . gasby supports so many things, so it occured to me, I need to glue them down. By looking at python and ruby development environments, javascript things look like mess to me. This is all personal opinion with limited knowledge. jekyll forces you to use a fix setup and everything binded at startup…If you have deeper knowledge, you tweak some, but for the most part, the framework is set and rigid. For example, you can not change template other than liquid…
As a summary gatsby seems like a more general solution for static web sites, not specifically blog etc.
Hugo seems viable, but like jekyll there seems to cases that you need take a look at go language stuff for example in templates. Jekyll strives to isolate site owner from internals, ruby, javascript etc. and if you can find a good theme that suits your purpose this can actually happen. Hugo brags about speed which is probably true, jekyll is or was notorious for being slow, but in my site I believe I will have long to time to hit performance issue by looking at my post count. I also count on the fact that since I write everything in asciidoc and can migrate or convert to almost anything. I also count on the fact that jekyll is very popular, so it would be easy to find migration tools to other frameworks, all of which are in hunt of user of popular frameworks, if it is dictated in the future. Jekyll itself has many migration tools from other popular environment. Jekyll is slow for the most part because of ruby…Ruby is losing ground because of performance so the performance improvements has become the focus of the language as far as I can see…Later ruby releases are much more faster than previous, and I hope that these improvements will control or prevent the future performance issues… It may never be as fast as go, whose speed can be compared with c, but I hope, it will be in acceptable levels…
As far as I can see jekyll gives very much importance to be inline with requirements of github, which also drives it popularity…Githus strict requirements and security issues makes jekyll much controlled framework…
If I have become more proficient in the future, I may try to use a framework like 11ty, which is the framework with the utmost flexibility, but similar ready to use structure… The downside of the 11ty for me was, it does not support asciidoc currently and it is javascript environment…which may not be issue for you…
In jekyll everytoolset has become ruby…There are not other dependencies as far as I can see or to the best of my knowledge…These are the result of more or less my one week search and evaluations based on personal view, preferences and background…
By the way I did not select pelican which is a very good python SSG, but only reason I did not chose it it does not support asciidoc…You see asciidoc is a very important factor for me which you may care less…