I've found productivity tools to be a rather personal thing and depends on how, where, and when you use them. If it's for work or academic use then high volume of notes is expected and so exporting is a concern, but for plodders that do low volume but over a long time then exporting by hand isn't such a chore.
I'm in the latter camp having collected notes over the years as more of an aide-memoire and code/text clippings. So for me I recently started to use Note Station as a handy way to have access to my small set of info, with formatting, tags, and grouping.
Having said this, my preference has been to use the plain text file system: a folder containing structured folders of text files. Guaranteed to be transportable, lots of editor apps on all platforms, works for years and years. Stick it on you cloud sync service of choice.
On Mac I use BBEdit and TaskPaper (plus the now free Folding Text) as they support markup/down formatting. On iOS I currently use Editorial (Dropbox sync only, hum), Taskmator, and Pretext. Plus can edit in Bash shell using vi / vim.
I suppose I should mention Windows too. I used to used TextPad but now use Notepad++.
And the PTFS can be enhanced to support other file formats (RTF, PDF, JPG, etc) by using a different app to open them! It's so flexible
