It appears that MDG is also working on integrating Meteor with Apollo based on Meteor Roadmap: GraphQL Data: SQL, REST, performance:
We are working on providing better tools and documentation for Meteor developers to integrate Apollo into their apps, and welcome contributions in this area. The next priority for Apollo and Meteor is enabling Meteor developers to choose to replace MongoDB entirely with GraphQL on top of other storage engines.
An official integration would be preferred over third party integrations, but we don’t know when that would happen (in version 1.7?). Since I want an integration now, in the meantime I’ve been looking at third party integrations, with one requirement being that it should be easy (i.e. wouldn’t require much code rewriting) to switch to the official integration when it becomes available. ddp-apollo is quite simple so would fit that requirement.
I will look further into cultofcoders:apollo to see whether it has enough advantages over ddp-apollo that make it worth switching to it before the official integration is released.