1. Choice of Node, DO has both US and EU location.
2. Scalable, Instantly Scale up to 96GB of Memory.
3. API - Dont think any of those VPS has those.
4. Hourly Billing.
And would you trust your hosting with Millions of VC backed money or a small VPS company? ( No offence, it is all part of perception and marketing )
I think for less then $10 hosting only, Ramnode and many others LEH wins. But if you want sometime in production that needs more power in the future DO have you backed.