I have abandoned storyboards as well for most of the reasons mentioned above, even though I’m working alone.
But, the most important advantage of using code instead of storyboard is I can write dynamic layout of views in a better way. Custom animations are not something that the storyboard could help with.
Connecting layout constraints outlet in storyboards, and managing them at runtime is quite a pain. Not to mention when there are auto layout issues, the storyboards will slow down the smoothness of using Xcode.