IMO, big benefits in billing per minute rather than hour, discounts applied automatically when running longer instances, up to 30% off for a whole month, rather than having to reserve it up front for discount, and instances that can be preempted vs the spot market(can save something like 70% off normal price). There's also the ability to customize proc and memory to your workload, so you're not paying for one or the other if you don't need it. They also recently added a feature that tells you if your vms are oversized for the work they've been doing, and what size would be most cost-efficient.

I've been using it for a dozen or so personal projects, and never paid more than $30 or so per month. That's probably about 50% less than what I was using at AWS, and I would never have had the ability to use tools like bigquery (redshift on AWS), hadoop, etc, just because I wouldn't want to spin up a cluster for hours. All the logs from all those projects are costing a few cents per month in bigquery.

If you just need a few servers for your side projects. You should use one of the cheap providers: Digital Ocean/Linode/OVH/Hertzner. They're just a lot cheaper.

If you need all the fancy features, typically because you're running a company (VPC, SAN drives, S3/cloud storage, load balancers...). You should use GCE instead of AWS. I'd say it's 20-50% cheaper in average.