Writing on Ghost with Ulysses and iA Writer
Up until recently this blog was hosted on Blot.im. For various reasons, mostly because I suck at front-end web development, I moved to a PikaPods-hosted version of Ghost where this blog is currently living (and should be living for a long time). Ghost has really good default themes and a ton of very good premium themes available (soon I'll be upgrading to Ubud from Aspire Themes) for those of us not talented in theme development. Blot is...not so good in that department.
When I was writing posts on Blot I was using the excellent iA Writer. I like writing in Markdown and Writer is an excellent Markdown editor that just writes to the file system and syncs to other iOS devices with iCloud Drive if you need that (and apparently they've brought back their Dropbox support recently on iOS). Writer also has built-in support for various blogging platforms like Ghost but their Ghost integration is pretty limited. You can post drafts to any Ghost install but that's about it.
I also have a Ulysses subscription that I've had for years that I don't do much with but I've used it on and off and love the app enough that I just haven't been able to bring myself to cancel the subscription (it doesn't hurt that I have the grandfathered yearly pricing that was given to previous owners when Ulysses first went to the subscription model).
Each application has it's strengths but Ulysses most definitely has more features for long-form writing. It also has a much better system of third-party integration than iA Writer does. Ulysses will auto-fill multiple properties of a post based on what is in certain sections of a document (called a sheet). You can also select whether to create a draft or publish a document. If you publish you can either publish immediately or schedule a post directly from Ulysses. Most importantly posts can be updated from within Ulysses which makes it very easy to use as your "source of truth" for your blog posts.
All that said, neither of these tools is a good as the Ghost web application for writing posts if you don't care about Markdown (and even for those that do there is a Markdown card available). If you want to be able to take full advantage of what Ghost has to offer (even basic things like creating pages instead of posts) the web UI is your best bet. If you do only go the web interface route make sure you have a good backup!