Even though it's not open source, just free(for very small projects), I have been really liking kitemaker.co I'm curious what other people think of their appro

Even though it's not open source, just free(for very small projects), I have been really liking kitemaker.co I'm curious what other people think of their approach, and whether that should be a model for open source kanban boards to follow. It's not Trello, which is way to flexible turning work items into a mess, but it's not Jira either. For me it seems to nicely fit the sweet spot of structure and ease of use.