At this point, I find the app frustratingly close to perfect.
I don't mind the iCloud storage, though I'd mind it far less if I could export a group of sheets as individual files.
If it had YAML or some other metadata support I'd buy it now.
The editing environment itself, as I've said, is the best I've ever used for prose.
But absent the YAML support it doesn't really help me. I'd just end up implementing a bunch of complicated workarounds to compensate.