We use Hyperapp to power our most complex UIs (decision trees, onboarding sequences, etc.). We didn't need any of the existing React ecosystem for that, and by removing React, we saw several benefits:

1. Smaller library for faster page loads

2. Simpler API, docs and library made it easy to get started and understand what's happening behind the scenes as well as debug any issues we faced

3. We aren't supporting a project run by Facebook, which I personally view as a good thing given Facebook's many previous issues. Facebook's patent clause (while it no longer exists) was a factor in our original decision.

I would choose Hyperapp again for my company, and I use it for personal projects as well.