One of my all-time favourite features is being able to animate individual objects of a group, and even still being able to animate the group itself!
But more generally, all the features come together very well to form what I know for a fact is hands down the best tool to create online e-learning content in HTML5 or *gasp* flash... It provides so many options and customizations that it will be guaranteed to work for your business needs.
Compared to the likes of Adobe Captivate, which has been around much longer, Articulate Storyline is already years ahead of Adobe. I was forced to use Captivate for a few months before switching to Articulate, so I can tell you first hand how terrible it was to work with Captivate, and how terrible their support team was.
I dislike that this is a Windows only application. I strongly hope they bring it to macOS in the future, as this is where all the creatives live. I am forced to use this application in a VM on my Mac, and the performance is hindered as a result.
I dislike not being able to move objects with the cursors pixel-by-pixel. I should be able to move by 10 pixels if I hold shift. This is a fairly common standard when it comes to applications like these, and it's unfortunate that Articulate doesn't support this interaction. I am forced to bring up the size/positioning window every time I want something to be pixel-perfect aligned.
The alignment guides are not very snappy, and somewhat difficult/annoying to use.
The animations are transitions are limited/archaic.
Generally, I would recommend looking to Keynote for inspiration when it comes to interacting with objects on slides, as well as animations. Keynote is years ahead of any type of slide creation tool I've ever used, and it would be really nice to see more of these types of features built-in to Articulate in the future.
There are SOME (very few) features in Adobe Captivate that aren not available in Articulate. However, there are so many more features in Articulate that are not available in Captivate that make the switch very worthwhile. Not to mention the ease of use, better support, and vision for the future of Articulate that this company has.
We are converting all of our old e-learning courses from flash to HTML5. The major benefit that Articulate offers us is in creating rich content that still somehow manages to stay low on file size once exported.