From my experience so far one big point in favor of DragonRuby is that its philosophy focuses on developer productivity, for example
- an iterative immediate feedback style of development using hot reloading
- (in the latest version) direct source code editing and updating via a HTTP Developer interface (think updating your smartphone game at runtime without re-deploying)
- Producing builds for all Desktop platforms in usually less than a minute (mobile and consoles probably take longer considering the surrounding tasks of signing apps, registering in stores etc)
- offering a centralized interface for persistent game state which is automatically dumped for error analysis in case of failure and able to be recorded/replayed/rewinded out of the box during dev
- Abstracting away File Systems/Storage mechanisms out of the box so you don't have to care about where you save on a Switch, PC or iPhone
and probably lots of other stuff I'm not quite aware of atm.
Another big plus point is the lively and encouraging Discord community