Dang, the people behind Brainio have just released a brand-new, all-rewritten version – currently free of charge! It does look extremely attractive (nice mixture of text, mindmapping and hybrid). More details on their website: https://brainio.com

Interesting to see how many notetakers are going down this route. Octarine is evolving in a similar direction, and of course it's built into Obsidian. Although Brainio's mindmapping is somewhat closer to the original concept (as embodied in Xmind, SimpleMind, etc.)