MarsEdit is the client most people mention as a Mac replacement for Windows Live Writer, but after using WLW for years and then trying MarsEdit, it didn't hold a candle to WLW. It's shocking--WLW is a free tool that hasn't had active development since 2012--but true.
The reason is probably that the market for blog editors disappeared when WYSIWYG editors became good enough for most people and wifi became common. The level of hassle "fat clients" in the space end up being (with crappy caches, blocking interfaces etc) is not offset by the tangible benefits of offline editing and marginally-better media support.
I'm not a great fan of the Blogger editor, but I've not found any modern alternative that can beat it so much to consider paying for it.
The Blogger editor was so bad, for writing a blog with any amount of code snippets, that I got frustrated enough to bail on Blogger entirely and write a simple hand-rolled blog engine. There was absolutely no way to get it to not mangle the resulting content - even directly editing the HTML wasn't really reliable.
