Arguably, Digital Ocean is more like a regular hosting provider with better onboarding. Plenty of hosters offer comparable infrastructure for the same price (you can even get something dedicated).
They're also far cheaper than AWS, where you pay a premium for the elasticity and access to the ecosystem. If there's anything to compare AWS with, it would be Google Cloud Platform, Azure and maybe Rackspace.
Digital Ocean is comparable to EC2. But AWS does LOTS more.
$40 / month for 4gb of ram, 4tb of transfer, and two cores, is very cost effective. Linode is also very reasonable.
If all I need is that scale of computing, what should I use instead that makes sense other than cloud services? Setting up colo or a dedicated box for that would be more expensive and a much larger hassle.