"enterprise grade" covers a a much larger spectrum of uses and needs with regard to features and stability than non-enterprise grade, making it kinda hard to answer that generally.
They offer VMs, containers, managed DB instance offerings, block storage, multiple regions and datacenters, load balancing, etc. They have an API to control all those things, and modules available in many popular languages. But that's basically what many people consider table stakes for a service like that, and indeed there are competitors like Vultr and Upcloud that offer the same.
Will any of them have quite the same level of offerings that AWS or GCE or Azure offer? Probably not. But for a great many people what they have is all the enterpise level stuff they'll need or use, and it is decidedly easier to just start up a cheap linux VM and take care of it on one of these services compared to AWS or GCE or Azure, so if what you want are somewhat manually managed cloud VMs, I highly recommend one of these services over one of the big names.
I've used all the services named, and I still prefer DO for just throwing up a cheap $5-$10 VM for personal stuff, or to spin up a temporary VM for testing something out. On DO that's a couple second process when you do it manually by clicking around.