I found only one opensource extendable WYSIWYG with comprehencive documentation and community - and that is CKEditor, this is the good part. Now, about the bad...
1) I need to catch a keyup event and CKEDITOR.editor.on is only takes key event which, as I understand, stands for keypres. I tried to make a workaround with $(ck.container.$), but for some reason the container property is undefied right after ck var is created. But it present in global scope in console after the whole page is loaded. Does the editor creation using unblocking operations? Or it is relying on css selectors rather than caching element links?
2) I included autogrow plugin on configuration stage, but for some reason autogrow event doesnt fireing.
3) though I turned line breaking into enterMode: CKEDITOR.ENTER_BR, on pasting blockquote I still having a <p> inside it. Where should I dig?
4) AutoGrow plugin doesnt work properly with source editing - the height of source remains unchanged
PS: I know these problems already were discussed, but most of these discussions are about versions 3 and below.