WizNote

Windows client is fully featured and very competitive but the Qt client for Linux and macOS is not.

Pros:

1. Multi-level directory. Compared to EverNote which only supports single-level directory.
2. Markdown-enabled. Just add .md to the end of note title, the note will be rendered as markdown.
3. Plugins. Some plugins are quite useful. For me it's WizHelper which can provide some useful information when I'm writing an article.
4. External editor. Internal editor is awful editing markdown notes. So I introduced Typora as external editor. Although there are some problems(See cons).
5. Official Qt client for macOS and Linux, compared to EverNote and OneNote which do not support Linux. For Arch-like distro users you can find it in AUR. But .... (See Cons).
6. You can choose you own sync methods. If you do not like to store data on the cloud, it can be used as a local notebook application. All data is stored as .ziw file. Simply unzip it and you can view it in HTML format. The whole dir can be synchronized by some methods you trust like Resilio Sync or Syncthing or GoodSync. Any way...See cons.
7. incremental synchronization. in new client it is faster. especially for users like me who tend to use it like a writer app. but the latest version has some bugs in incremental sync.

Cons:

1. Internal editor is toooo simple (especially for markdown editing). Although there are some fancy editor plugins but some features like copy & paste image inline directly in the editor is only supported by the internal editor.
2. Qt client is not competitive. There are some bugs and it lacks lots of features compared to windows client. eg, shortcut to switch between editing mode and reading mode, note templates, auto sync when a note is edited, etc.
3. Even if be used as a local notebook app, you still need to register an account to use the client. I hope the dev team to consider a way to use the app anonymously and locally.
4. The team is not international. The official forum is Baidu Tieba and in Chinese. For me it's not a problem but maybe for you it is. And the support is not very satisfying. I issued a bug some weeks ago, there's no reply. I even do not know if they received my feedback.

[Edited by 543685015, July 06]

WizNote looks like a gift for open source enthusiasts looking for an Evernote replacement. The problem is that it uploads your data to Chinese servers without explaining how that data is stored, what your rights are, who has access or what happens if you cancel. There is no mention of, e.g. encryption, either. If you value the privacy or security of your data, you should stay well away from WizNote. Who knows what it does with your information.

Stay far away! This app is only partially open-source (at best), and should not be classified as such. How much is anyone's guess, but as of now the Github shows almost zero activity while the mac/ios app versions are frequently updated.

Every notes has a dedicated folder that contains the note itself (in zipped html format) and attached files. Well organized and easier to manager compared with some other note apps using a single database file to store everything.

Official Support Linux and Web/Android is very powerful

Outed looking user interface

The application is not presented entirely in English. It seems made for a Chinese audience, and all hyperlinks/docs are in Chinese. You'll get Chinese emails. You'll see Chinese messages. The main application UI is in English and you can use it, and the UI is slick and uncluttered, but I just couldn't live with the Chinese so have migrated to Zim (in conjunction with Dropbox).