Every year or two, I get all excited about the possibilities of using Evernote to record and organise my life, then I remember why I abandoned it the last time - it's so difficult to organise things.
Yes, there are tag-related workarounds, but why can't I do what I've been doing on my mac for the last 25 years - put folders within folders (or 'Notebooks' if you insist)?
By FAR the simplest and most intuitive method IMHO.
Come on Evernote - people have been asking for this for YEARS!