I use Uploadcare because of the simpler API for integrating to my current stack. I've looked around (ie. Cloudinary, etc.) but Uploadcare definitely has the most straight forward approach with their API.
We use Uploadcare with Netlify CMS. They have included advanced media support via Uploadcare and it has been working great!
Uploadcare has saved me countless hours/dollars/grief by offering an amazing file management & processing platform with a phenominal user interface that I can embed right in my web app. It terrifies me just thinking about life without Uploadcare. I recommend it to everyone I know!