There is a method that has been created to unite the core benefits of both approaches: "iMapping" is based on hierarchical structure that also allows to map interrelations. Additionally, since it is based on nesting and zooming, iMaps can become very large with many thousands of items without sacrificing overview. iMapping unites the hierarchy of Mind Maps and the simplicity of pin boards with the network structure of concept maps. Update: The all new Version of the original iMapping Tool is infinitymaps.io

Here is a short youtube video to give an impression about it.

-- Disclaimer: Yes I have stakes in iMapping. It was my PhD project to create it and it is my current business to run a startup around it. My above claims however have been repeatedly validated by customers and free users. A permanently free version of the iMapping Tool / Infinity Maps is available.)