I've used lektor and pelican but not nikola. Lektor provides a nice gui where pelican does not (ime). They both work well and pelican seems to have more themes

I've used lektor and pelican but not nikola. Lektor provides a nice gui where pelican does not (ime). They both work well and pelican seems to have more themes due to it being older. I ended up with wordpres (shrugs).