I find MobileOrg's workflow clumsy to work with. I wish it would just allow me to browse a directory in my Dropbox and leave the syncing to Dropbox itself.
I'm a MobileOrg user, and I completely agree. I would pay good money for an app that presents an iOS user interface for editing files with org-mode markup, including creating org-mode files on the fly. Unfortunately, MobileOrg offers neither of those features.
MobileOrg is free software (https://github.com/richard/mobileorg), but it's so far from what I'm looking for that it might just be easier to start from scratch.