Been using way too many apps in the past twenty years. AskSam on Windows in the 90s until early 2000s. Then they stopped developing it. Exported my notes in HTML format, waiting to be migrated into my latest tool. - Then when the iPhone arrived tried to do note taking on it. Used Momonote app (still exists, but practically abandonware), created a couple of thousand notes. Exported them as csv, waiting to be migrated... Then Evernote. Excellent tool. I have 12k notes in it. Love it. Still use it. Paying member. In between tried to migrate from Windows to Ubuntu. Started using Emacs+Org (several hundred notes in there, waiting to be migrated). But also ZimWiki. Then moved to Mac/OS. Went back to Evernote. Currently using a combo of Evernote and Bear Writer app. Love Bear. Has a phantastic UI, markdown, super fast interface, syncs with all my iDevices.

But I am aware that in twenty years from now none of these tools might be alive anymore. I keep exporting and backing up my data because of this. And my backlog of "to be migrated" grows longer and longer.

For now I find it more convenient to use a tool with a sleak interface that offer all the features I need in a "personal wiki" / note taking app: inserting screenshots into notes (this is a killer feature for me), beutifully rendering my markdown text, fulltext search, nested folders (or tags in Bear lingo), syncing across all my devices. The alternative is too cumbersome: For instance Emacs/Org + rgrep + Dropbox for syncing + git + a bunch of .emacs entries that allow me to insert screenshots.

Edit: Forgot to mention IdeaNote. Used it when I tried to replace my iPhone with a BlackBerry device. Excellent app. I could create super long and time stamped journal entries / logs / notes on the superb keyboard of the BB device in seconds (never got used to typing on a touchscreen). But eventually the BB got abandonware itself. And so the app. Luckily I could pay 50$ to export my 3k notes. Migrated them successfully to Evernote with a bit of Ruby script.

Edit 2: Lesson learned for me: No tool is going to be there forever. Need to have a clear concept for how I will keep my data independent from tools du jour.