At Hashnode we are using Cloudinary and are pretty happy with it. I am not sure what type of projects you are working on, but Cloudinary is great for content driven sites like us. We show different versions of the same image on different pages. Doing this manually i.e resizing, cropping, detecting face, generating thumbs etc is a little painful. This is where Cloudinary does a great job.
They have released SDKs for many languages - this is definitely a plus. As Cloudinary uses Akamai to serve your images, you also get speed. Previously we were using S3/Cloudfront combination to store and serve images, but I found cloudfront to be slow. Cloudinary, on the other hand, is doing a great job in both image storage and delivery.