The mind mapping format provides with a clear overview of connections, hierarchies and relationships of notes. At the same time, it's possible to add more detailed notes, links, pictures and even whole files to the keywords, so that no important information gets lost.
You can only work completely offline when using an iOS or Android device. For your browser there's only a clumsy 'offline mode' available. If you didn't hit the switch before you have the need for working offline (for instance: in a meeting, at a customer's location, in a plane,
Evernote is the number one 'store-everything-archive' when it comes to unstructured data or information. MindMeister markets there Evernote integration as a very cool feature. But this integration is very basic and buggy: only the last 50 (?) notes from Evernote's default notebook are...
XMind has preset templates available that allow getting started quickly. There are templates for project planning, status reports, dashboards, organizational charts, swot analysis, timelines, decision trees, weekly plans, among others.