For notes I use Letterspace. I like it because you can organize within the note itself using hashtags and @mentions. The way I use it is that I have my main categories as the hashtags, and then the @mentions as my general tags like @advice, @articles, and whatever. It doesn't have image support, but I can easily use a Workflow to deal with that. I actually use it to make rich text versions of my Markdown at this point.
For writing, I use Write. It works on the iPhone, iPad, and Mac, so that's the big reason I use it. I like that I can tag things too. The Markdown hybrid previewing is really nice too.
You can do tables with it, but it's not as nice as doing it in a proper word processor, heh.
Some people like to use Drafts for writing, but I just like using it for... Gasp... Drafts!
I don't like using the same app for everything because it gets too confusing since I do too many things. The other problem I had was that my Evernote got to the point that it wouldn't sync anymore.