Personally, I like AWS because of it's vast amount of services that mostly work very well together. As long as we're not comparing to Azure or Google, that is a huge advantage. But even with Azure and Google, in my humble opinion (have used later 2 only sparingly) amount of services interconnected is much larger. In example others are still catching up with AWS Lambda.
Also, for smaller projects, Amazon free tier is excellent argument. I've just worked on a project where I connected AWS Cognito user pooling, AWS API Gateway (which uses Cognito for user authentication), AWS Lambda which sits between API Gateway and AWS DynamoDB and forms API backend. Cognito's free tier is up to 50000 (active!) users per month, Lambda is free up to about 1,000,000 secods of execution time, DynamoDB also has free tier and is not small. If you build single-page app you can put it on S3 (I used Netlify) and get free or almost free static host too.
Basically, yo can end up with serverless, scalable and free hosting for solid sized apps.