I’ve been working with Scrivener for about a year now and one of its strengths is the ability set one flat file as your main file that contains all your research, characters, locations, and subplots. In addition, It was easy to setup automatic backup to my Dropbox account so that using it from any device, I would see the same content. My primary device is my iOS device but on occasion, I will be on my iPhone with ideas. The same goes for my windows notebook as well as my macOS vm both running Scrivener 3.
After reading that David Henson, the British writer of Spain and The Killing, completely did a 180 and instead of endorsing Scrivener, he now prefers Ulysses, I figured I’d better do some due diligence and try Ulysses.
One of the first things I noticed about Ulysses is that there is no Windows version, it offers a direct WordPress blogging feature (which Scrivener does not) and beyond the 14 day trial, available via subscription only for all devices at $4.50/month or $39/year. This contrasts with Scrivener which is $19.99 for the iOS version, $45 for the macOS version and $40 for the Windows version (there was a Linux version of Scrivener but that project was abandoned.) From an return on investment standpoint, a user of Scrivener on all the devices that I use will have paid $104.99 vs $39/year for iOS and macOS platforms. It would seem that you would get upgrades and be ahead of the game for almost three years if you went the Ulysses route. Scrivener has a very slow development cycle so the time from Scrivener 2 to the recent version 3 for macOS and the upcoming windows release (currently in beta) means you would actually be ahead of the game if you went the Scrivener route.
Both Scrivener and Ulysses offers Dropbox external sync but Ulysses also uses Apple’s own iCloud storage for sync services.
Personally I did not find Ulysses to be very intuitive. Setting up Dropbox worked well enough but it wasn’t readily apparent how to make sure automatic backup works. Scrivener specifically has a preferences dialog that sets the auto backup function (and complains if you use the same folder for backup as your main document repository.) Making iCloud work was supposed to be automatic but I wasn’t able to get it working yet between my iOS platforms and macOS vm.
Ulysses offers Markdown support and Scrivener also can import and export markdown using the Fletcher Penney multimarkdown syntax. Numerous bloggers use Scrivener for blogging and have published templates here. This site includes the steps for utilizing the Markdown language into WordPress.
Both programs offer a full screen mode that i personally use to great effect but I preferred the complexity of Scrivener should I want it vs. the simplicity of Ulysses.
Gary Gibson offers his reasoning for preferring Scrivener over Ulysses here. That review was before the iPad version of Scrivener but his conclusions are valid.