Simplenote would be the canonical example. BoostNote, which I think was an earlier HN item. QOwnNotes, if you like ownCloud. Turtl, if you like eliding the silent 'e'

Honorable Mention Notational Velocity (Mac-only)

I moved to Quiver from Evernote, also Mac-only. The solo dev moved to Berlin a little over a year ago, and I would describe the app as minimally supported at this point.

I've been at this a long time, and have run the gamut from Evernote to tagged text files managed in Emacs with some custom macros, long before org-mode was even a gleam in the eye of Carsten Dominik. So I've seen them all, and as noted by many other folks, the rules boil down to one - must have a portable base storage format (preferably Plain Old Text) and/or solid import and export to some such portable storage format.

If it's commercial software, pricing will get stupid and/or bug-ridden features that add bloat and that I don't want are added to justify said pricing; the product/company is sold to someone who will do the above; the product/company dies. If it's open source, more or less the same, with the additional stage of becoming closed/proprietary/commercial, which then reduces to the first case. I kind of assume at this point that I will be moving to a different platform every 4 years or so.