I'm testing out MarsEdit and it's really cool - apart from one lacking thing: Support for Zemanta images. That would really make my month!
It would make it so much easier to have images at your fingertips for your blog-posts, and not having to search them all out first or add them later, when you have found the right one.
I've searched the forum and find posts like this one: http://www.red-sweater.com/forums/discussion/comment/10268#Comment_10268
which is quite old... And worthy of note is that recently Zemanta has been added to Google docs as well as support other types of blogging applications (but sadly those apps are for windows).
I seriously think it would be a great time to reconsider adding support for this, as that really would optimise the blogging experience for your customers, as well as be a great sales-point by now. Much have changed since 2011 ;)
Another thing that would be really cool, would be the posibility to share the post you have just written, via i.e twitter, facebook, google+ and/or linkedIn. Especially the first 2 would be my preference.
Anyway, just my 2 cents. I'll most likely end up buying MarsEdit anyway, but I REALLY would love to see the Zemanta support inside the app. :)