Members don’t have traditional passwords
When visitors subscribe to become members, Ghost doesn’t store passwords for them. In order for a member to login, they enter their email address, Ghost emails them a magic link, and they’re authenticated after they click the link. Having switched from WordPress to Ghost as well, I didn’t realize this until much later.
Only members can comment
With regard to comments, and this is by design, only members (i.e. people with an account) can leave comments. Because of this, migrating comments isn’t straightforward, because you would essentially need to create an account for each commenter. I didn’t do this, because it didn’t feel right to create accounts for people without their consent.
I mention this, because in WordPress, leaving a comment and having an account are two different things.
Along those lines, far fewer people comment now, because most don’t want to sign up to become a member just to leave a comment, but this was expected, because I’m like this myself.
No media management
The one thing I do miss is some kind of media management. For example, when I upload featured images or add an image gallery to a blog post, there isn’t a way to see everything I uploaded. And when you remove uploaded images from a post, I think they stay on the server. I always connect to the server and remove them manually.
Overall
I love the publishing experience in Ghost. I’ve used WordPress personally and professionally for over 10 years (and still do), but I appreciate the simplicity of the Ghost interface. You get many features for free (newsletter, subscriptions), you’re nudged to focus on writing vs. spending time creating layouts, and themes are interchangeable (whereas in WordPress, many themes have fine-tuned settings that don’t carry over from theme to theme).
The best way to experience Ghost coming from WordPress is to avoid trying to recreate WordPress functionality in Ghost, but rather ask yourself: how can I simplify?
For example, in WordPress you have categories and tags, but in Ghost you only have tags. Simplify.
In WordPress you can build many complex menus, but in official Ghost themes, the menus are lean and limited to a primary and secondary navigation. Simplify.
Now, I’m only talking about out-of-the-box Ghost features. I’m sure with custom development it would be possible to extend Ghost to do more, but I’ve used this opportunity to keep things simple. In fact, that was a big driving factor for switching.
Hope this helps!