Let's start by saying that DO has fewer features for a complex deployment:
No load balancing,
no private subnets,
(IIRC) no IPv6 at the moment.
No "cloud files" or S3 equivalent,
the scaling isn't as automatic as RAX or AWS can provide.
DO can't host Windows (which still matters for many existing operations, don't fool yourself).
RAX gives more information and granularity on its VM levels.
Finally, support. RAX can do managed services, dedicated advisors, IT support and servers for sensitive data. DO has none of this.
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There are two things DO does that I appreciate (though neither concept is new):
* $5 hosting. RAX is a minimum of $16/mo now, for the same VM strength.
* Application deployments. The ability to one-click deploy Wordpress/Gitlab/etc. is pretty damned awesome.
DO is great for technically competent people who don't need a lot of infrastructure, or otherwise have a consistent level of server/bandwidth requirements for their servers.