Let's add to this the fact that if you're under a DOS attack with DigitalOcean they disconnect your machine from the internet (making it impossible for you to log in and do log analysis, etc.), send you an email saying "figure out what's happening and stop it", and then reconnect your machine several hours later only to repeat the process practically as soon as it's back online (assuming the DOS continues). I wouldn't trust a side project on DO, let alone my business.
Just to clarify, DigitalOcean does not offer any form of DoS mitigation services so they blackhole during a DoS. Its for 3 hours, a lot less than other providers.
If you've got a DoS issue, you definitely need a 3rd party DoS protection service. Cloudflare free works pretty well
It's not "a lot less than other providers". You know what happens when someone starts DDOSing one of my AWS servers? I get a CloudWatch alert saying "high inbound traffic" and that's it. They don't black hole the thing and cut off all traffic. Then, I can log in, see what's happening, and take my time diagnosing the problem. Even under a fairly heavy DDOS I never feared losing access. With DO, the black hole happens before the email alert. It's a terrible policy and I can't use or recommend DO until it's changed. I can't stick CloudFlare in front of every server I own.